Alert Type Model Summary

Use this topic for a high level summary of each alert type, whether it is based on Analytics or Machine Learning (and what type), and the training time required for each. Optionally, expand any alert name for more specifics on that alert type.

  • Machine Learning (ML): Stellar Cyber's powerful artificial intelligence system uses a variety of models to analyze data and may aggregate many alert logs to generate one Stellar Cyber alert.

    • Unsupervised ML  – Unsupervised models power the alert types that look for dissimilarities from normal patterns. These models learn the normal pattern within a certain customer environment, such as what application usage is normal for which users. Then, after that initial learning period, the alert types trigger when activity appears significantly different from the observed normal pattern. Similarly, a user observed using an anomalous application would result in a trigger of this alert type. Unsupervised Machine Learning is applicable when there is no clear identifier for what "bad" looks like.

    • Supervised ML  – Supervised models power the alert types that look for known bad patterns based on training performed on large scale datasets. An example of a bad pattern here is a recently registered domain used for data exfiltration. There are enough real world examples of this type of activity that a model can be constructed to identify it with a certain level of confidence. Supervised machine learning models require no customer training period because they are already "trained" and ready to be used. In summary, Supervised Machine Learning is used when there are clear identifiers for what "bad" looks like, but it is far too computationally complex for a simple "rule" to be used.

    For more details, refer to the overview of Machine Learning and the details for each alert type that may be produced in the Machine Learning pathway.

  • Analytics – These prediction results are based on security rules. These alert types leverage simple arithmetic or logic conditions instead of machine learning. For example, a Bad Reputation alert may trigger if a source IP has a reputation of "Bad Reputation". Another example could be looking for suspicious RDP activity that matches a certain process name. You can also use Stellar Cyber's Statistical Analysis engine to create your own Automated Threat Hunting rules. Additionally, you can configure external Threat Intelligence feeds which are reported as Emerging Threat alerts, although the data may contribute to other Machine Learning alerts.

Training Time

Certain ML models learn the data distribution in your network automatically but require two weeks of observing data to create an approximation of the real distribution. After that baseline, the model is automatically updated every 24 hours. Use the table below as a guide for which need to run in your environment for two weeks to begin reporting.

XDR Display Name

Model Type

Machine Learning Model Requires Two Weeks

Abnormal Parent / Child Process

A process that typically launches a small, consistent number of child processes has launched a new child process. Investigate the new child process or the parent process to see if it is benign.

This alert type has two subtype categories:

Alert Subtype: Machine Learning Anomaly Detection

XDR Kill Chain

  • Kill Chain Stage: Persistent Foothold

  • Tactic: XDR EBA (XTA0001)

  • Technique: XDR Process Relationship Anomaly (XT1002)

  • Tags: []

Event Name

The xdr_event.name for this alert type in the Interflow data is parent_child.

Severity

25

Key Fields and Relevant Data Points

  • process_name — name of the process 
  • parent_proc_name — name of the parent process  
  • hostip — host IP address
  • hostip_host — host name
  • stability — score measuring the time since the parent process launched the last child process
  • diversity — score measuring the number of child processes that the parent process spawned
  • days_stable — time since the parent process launched the last child process
  • child_count — number of child processes that the parent process spawned

Use Case with Data Points

Each pair of parent/child processes (parent_proc_name and process_name) is examined periodically. If a parent process (parent_proc_name) with a small number of child processes (diversity, child_count) has not launched a new child process (process_name) for a long time (stability, days_stable) launches a new child process from a host (srcip_host), an alert is triggered.

Alert Subtype: Rule Based Detection

The Parent/Child Suspicious Process Creation rules are used to identify suspicious activity with parent/child relationships associated with process creation. Any one or more of these will trigger the Parent/Child Suspicious Process Creation alert types.

Key Fields and Relevant Data Points

  • hostip — host IP address 
  • hostip_host — host name
  • stellar.rule_id — Stellar Cyber rule ID

Link to Rule-Based Alert Types

Rules Contributing to Parent/Child Suspicious Process Creation Alert Type

Unsupervised

Y

Account MFA Login Failure Anomaly

An anomalously large number of Multi-Factor Authentication (MFA) user login failures was observed for an account. Check with the user.

This alert type has two alert subtypes:

Alert Subtype: Machine Learning Anomaly Detection

XDR Kill Chain

  • Kill Chain Stage: Initial Attempts

  • Tactic: [External] Credential Access (TA0006 )

  • Technique: Brute Force (T1110 )

  • Tags: [External]

Event Name

The xdr_event.name for this alert type in the Interflow data is cloud_account_login_failure_okta.

Severity

45

Key Fields and Relevant Data Points

  • srcip_usersid — cloud account user ID  
  • srcip_username — cloud account user name
  • event_summary.total_failed — number of failed logins in the period
  • event_summary.total_successful — number of successful logins in the period
  • event_summary.total_fail_ratio — percent of failed logins in the period, which is: event_summary.total_failed / (event_summary.total_failed + event_summary.total_successful)
  • weighted_anomaly_score — net score based on weighted rating of successful versus failed attempts (scanning, login, or other). Scores greater than upper threshold are potentially malicious and less than lower threshold are benign.
  • srcip_host — host name of corresponding source IP address
  • login_type — type of login
  • srcip_reputation — source reputation

Use Case with Data Points

Multi-Factor Authentication login failures and successes are calculated periodically for every account (srcip_usersid). If the number of failures is significantly larger than the number of successes, an alert is triggered. A sample Interflow includes the login type (login_type), source host (srcip_host), and source reputation (srcip_reputation).

Alert Subtype: Rule Based Detection

The Suspicious AWS Login Failure rules are used to identify suspicious AWS account login failures. Any one or more of these will trigger the AWS Cloud Account Login Failure alert type.

Key Fields and Relevant Data Points

  • eventSource — source of event 
  • eventName — name of event 
  • eventType — type of event
  • userIdentity.accountId — key ID for the account involved in the event
  • userIdentity.userName — user name of the account involved in the event
  • userIdentity.type — type of account involved in the event
  • stellar.rule_id — Stellar Cyber rule ID

Link to Rule-Based Alert Types

Rules Contributing to Suspicious AWS Login Failure

Unsupervised

N

Application Usage Anomaly

An internal application had an anomalously large number of connections to one or more external hosts in a measured interval, exceeding 99.99% of all other intervals corresponding to different applications in the past two weeks.

Investigate the application and connections, and consider blocking connections from the application.

XDR Kill Chain

  • Kill Chain Stage: Initial Attempts

  • Tactic: [External] XDR NBA (XTA0002)

  • Technique: XDR App Anomaly (XT2003)

  • Tags: [External; Network Traffic Analysis]

Event Name

The xdr_event.name for this alert type in the Interflow data is pripub_appid.

Severity

15

Key Fields and Relevant Data Points

  • appid — application ID  
  • appid_name — application name
  • actual — actual number of connections in the period
  • stellar.threshold — threshold number of connections per interval below which 99.99% of all other intervals, corresponding to different applications in the past two weeks, fall
  • srcip_host — host name of a sample source IP address
  • srcip_geo.countryName — source country
  • dstip_host — host name of a sample destination IP address

Use Case with Data Points

Every application's (appid) number of connections is calculated periodically. If an application’s connections (actual) are larger than the threshold (stellar.threshold) below which 99.99% of all other intervals corresponding to different applications in the past two weeks fall, an alert is triggered. The Interflow includes a sample source host (srcip_host), the source country (srcip_geo.countryName), and a sample destination host (dstip_host). If there are multiple source or destination hosts, view the list in the Original Records.

Unsupervised

Y

AWS AMI Made Public

An AWS AMI was made public. Check with the user to make sure this was intentional.

XDR Kill Chain

  • Kill Chain Stage: Propagation

  • Tactic: Privilege Escalation (TA0004 )

  • Technique: Valid Accounts (T1078 )

  • Tags: []

XDR Event Name

The xdr_event.name for this alert type in the Interflow data is aws_ami_public.

Severity

70

Key Fields and Relevant Data Points

  • userIdentity.accountId — key ID for the account  
  • userIdentity.userName — AWS account user name
  • userIdentity.type — AWS account type
  • eventName — AWS event name
  • eventSource — AWS event source
  • eventType — AWS event type

Use Case with Data Points

For each AWS account (userIdentity.accountId), activity to make an AMI public is monitored. If an AMI is made public, an alert is triggered. The Interflow includes the account ID (userIdentity.accountId), user name (userIdentity.userName), account type (userIdentity.type), AWS event name (eventName), AWS event source (eventSource), and AWS event type (eventType).

Analytics

N

AWS Logging Stopped

AWS CloudTrail logging was stopped. Check with the user to make sure this was intentional.

XDR Kill Chain

  • Kill Chain Stage: Persistent Foothold

  • Tactic: Defense Evasion (TA0005 )

  • Technique: Impair Defenses (T1562 )

  • Tags: []

Event Name

The xdr_event.name for this alert type in the Interflow data is aws_stoplogging.

Severity

70

Key Fields and Relevant Data Points

  • userIdentity.accountId — key ID for the account  
  • userIdentity.userName — AWS account user name
  • userIdentity.type — AWS account type
  • eventName — AWS event name
  • eventSource — AWS event source
  • eventType — AWS event type

Use Case with Data Points

For each AWS account (userIdentity.accountId), log disabling is monitored. Logging is enabled by default, so if logging is disabled, an alert is triggered. The Interflow includes the account ID (userIdentity.accountId), AWS account user name (userIdentity.userName), AWS account type (userIdentity.type), AWS event name (eventName), AWS event source (eventSource), and AWS event type (eventType).

Analytics

N

AWS S3 Ransomware

Possible AWS S3 ransomware was observed. Check with the user.

XDR Kill Chain

  • Kill Chain Stage: Exfiltration & Impact

  • Tactic: Impact (TA0040 )

  • Technique: Data Encrypted for Impact (T1486 )

  • Tags: [Malware; Ransomware]

Event Name

The xdr_event.name for this alert type in the Interflow data is aws_s3_ransomware.

Severity

90

Key Fields and Relevant Data Points

  • userIdentity.accountId — key ID for the account  
  • userIdentity.userName — AWS account user name
  • userIdentity.type — AWS account type
  • eventName — AWS event name
  • eventSource — AWS event source
  • eventType — AWS event type

Use Case with Data Points

For each AWS account user name (userIdentity.userName), suspicious S3 ransomware is monitored. If ransomware is detected, an alert is triggered. The Interflow includes the account ID (userIdentity.accountId), AWS account user name (userIdentity.userName), AWS account type (userIdentity.type), AWS event name (eventName), AWS event source (eventSource), and AWS event type (eventType).

Analytics

N

Azure AD Apps Modified To Allow Multi-Tenant Access

Azure AD observed an application being modified to allow multi-tenant access. Check with the organization to be sure this was expected.

XDR Kill Chain

  • Kill Chain Stage: Persistent Foothold

  • Tactic: Persistence (TA0003 )

  • Technique: Account Manipulation (T1098 )

  • Tags: []

Event Name

The xdr_event.name for this alert type in the Interflow data is azure_ad_add_app_multitenant.

Severity

75

Key Fields and Relevant Data Points

  • srcip_usersid — user ID that modified the property change 
  • activityDisplayName — description of the action
  • targetResources.modifiedProperties.displayName — properties that were changed

Use Case with Data Points

If Azure AD detects any user (srcip_usersid) changing an application to allow multi-tenant access, an alert is triggered. A sample Interflow includes the user ID (srcip_usersid), activity name (activityDisplayName), and name of the changed property (targetResources.modifiedProperties.displayName).

Analytics

N

Azure AD Custom Domains Changed

Azure AD observed a custom domain being changed. Check with the organization to be sure this was expected.

XDR Kill Chain

  • Kill Chain Stage: Persistent Foothold

  • Tactic: Defense Evasion (TA0005 )

  • Technique: Domain Policy Modification (T1484 )

  • Tags: []

Event Name

The xdr_event.name for this alert type in the Interflow data is azure_ad_change_domain.

Severity

75

Key Fields and Relevant Data Points

  • srcip_usersid — user account that made the domain change  
  • activityDisplayName — activity display name
  • activity_name — action description
  • targetResources.modifiedProperties — properties that were changed

Use Case with Data Points

If Azure AD detects any user (srcip_usersid) changing a custom domain, an alert is triggered. A sample Interflow includes the user ID (srcip_usersid) and activity name (activity_name).

Analytics

N

Backup Catalogs Deleted by Ransomware

The wbadmin.exe utility was used to delete the backup catalog. Ransomware and other malware do this to prevent system recovery. Check with the user.

XDR Kill Chain

  • Kill Chain Stage: Persistent Foothold

  • Tactic: Defense Evasion (TA0005 )

  • Technique: Indicator Removal on Host (T1070 )

  • Tags: [Malware; Ransomware]

Event Name

The xdr_event.name for this alert type in the Interflow data is ransomware_delete_backup_catalogs.

Severity

80

Key Fields and Relevant Data Points

  • hostip — IP address of the host on which the ransomware action happened 
  • hostip_host — host name
  • process_name — name of the executed process
  • event_data.CommandLine — command that was executed to delete the backup catalog

Use Case with Data Points

If wbadmin.exe is used to delete the backup catalog, an alert is triggered. The Interflow includes the host IP address (hostip), process name (process_name), and command line (event_data.CommandLine).

Analytics

N

Bad Destination Reputation Anomaly

A destination IP address with a bad reputation has received an anomalously large number of connections. Investigate the connections and consider blocking the destination IP address.

XDR Kill Chain

  • Kill Chain Stage: Persistent Foothold

  • Tactic: XDR Intel (XTA0005)

  • Technique: XDR Bad Reputation (XT2010)

  • Tags: [Network Traffic Analysis]

Event Name

The xdr_event.name for this alert type in the Interflow data is dstip_bad_reps.

Severity

30

Key Fields and Relevant Data Points

  • dstip — destination IP address  
  • dstip_host — destination host name
  • dstip_reputation — destination reputation
  • actual — actual number of connections to the destination IP address in the period
  • typical — typical number of connections to the destination IP address
  • srcip_host — source host name
  • srcip_reputation — source reputation
  • appid_name — application name

Use Case with Data Points

The number of connections for every destination IP address (dstip) with a bad reputation (dstip_reputation) is calculated periodically. If a destination IP address's number of connections (actual) is much larger than the typical historical number (typical), an alert is triggered. The Interflow includes the source IP address making the connection (srcip_host), the application (appid_name) used, and the reputation of the source host (srcip_reputation).

Unsupervised

Y

Bad Reputation Login

A successful login was observed from an IP address with a history of malicious activity. Check with the user.

XDR Kill Chain

  • Kill Chain Stage: Initial Attempts

  • Tactic: [External] XDR NBA (XTA0002)

  • Technique: XDR Bad Reputation (XT2010)

  • Tags: [External]

Event Name

The xdr_event.name for this alert type in the Interflow data is bad_reputation_login.

Severity

50

Key Fields and Relevant Data Points

  • srcip — source IP address  
  • srcip_host — source host name
  • srcip_reputation — source reputation
  • source_geo.countryName — source country
  • dstip_host — destination host name
  • login_type — type of login
  • username — user name

Use Case with Data Points

The login records are checked for every source IP address (srcip). If a source IP address has successful login records and its reputation (srcip_reputation) is bad (except brute-forcer and scanner), an alert is triggered. A sample Interflow includes source IP address (srcip), source host (srcip_host), source reputation (srcip_reputation), source country (srcip_geo.countryName), login type (login_type), and user name (username).

Analytics

N

Bad Source Reputation Anomaly

A source IP address with a bad reputation has made an anomalously large number of connections. Investigate the connections and consider blocking the source IP address.

XDR Kill Chain

  • Kill Chain Stage: Initial Attempts

  • Tactic: [External] XDR NBA (XTA0002)

  • Technique: XDR Bad Reputation (XT2010)

  • Tags: [External; Network Traffic Analysis]

Event Name

The xdr_event.name for this alert type in the Interflow data is srcip_bad_reps.

Severity

30

Key Fields and Relevant Data Points

  • srcip — source IP address  
  • srcip_host — host name of corresponding source IP address
  • srcip_reputation — source reputation
  • actual — actual number of connections in the period
  • typical — typical number of connections from the source IP address
  • dstip_host — host name of corresponding destination IP address
  • dstip_reputation — destination reputation
  • appid_name — application name

Use Case with Data Points

The number of connections for every source IP address (srcip) with a bad reputation (srcip_reputation) is calculated periodically. If a source IP address's number of connections (actual) is much larger than the typical historical number (typical), an alert is triggered. The Interflow includes the application (appid_name) used and the reputation of the destination host (dstip_reputation).

Unsupervised

Y

Carbon Black: XDR Anomaly

On a specific device, an anomalously large number of VMware Carbon Black endpoint log records or a rarely seen type of record has been observed compared to the typical number in a measured interval.

XDR Kill Chain

  • Kill Chain Stage: Persistent Foothold

  • Tactic: XDR EBA (XTA0001)

  • Technique: XDR Anomaly (XT1000)

  • Tags: []

Event Name

The xdr_event.name for this alert type in the Interflow data is carbonblack_edr_anomaly.

Severity

30

Key Fields and Relevant Data Points

  • hostip — device internal IP address  
  • host.external_ip — device external IP address
  • actual — actual volume of log records in the period
  • typical — typical difference in volume of log records between this period and the previous period

Use Case with Data Points

The number of occurrences of Carbon Black endpoint (cloud) log, based on the “UNKNOWN“ threat category (event.type), is tabulated periodically. If this category occurs (actual) much more often compared to its history (typical) or a rarely seen type of record is observed, an alert is triggered. The Interflow includes information such as the file name (file.name), process (process.name), and description (xdr_event.description).

Unsupervised

Y

Command & Control Reputation Anomaly

An anomalously large number of connections were made to known command and control servers. Investigate the connections and source hosts. If malicious, block the IP addresses of the command and control servers.

XDR Kill Chain

  • Kill Chain Stage: Persistent Foothold

  • Tactic: XDR Intel (XTA0005)

  • Technique: XDR Command and Control Reputation (XT5001)

  • Tags: [Network Traffic Analysis]

Event Name

The xdr_event.name for this alert type in the Interflow data is cnc_reputation.

Severity

70

Key Fields and Relevant Data Points

  • dstip — destination IP address  
  • dstip_host — destination host name
  • dstip_reputation — destination reputation
  • actual — actual number of connections in the period
  • typical — typical number of connections to the destination IP address with a C&C reputation
  • srcip_host — host name of corresponding source IP address
  • srcip_reputation — source reputation
  • appid_name — application name

Use Case with Data Points

The number of connections for every destination IP (dstip) with a command and control reputation (dstip_reputation) is calculated periodically. If a destination IP has a much higher number of connections (actual) than its history (typical) in any period, an alert is triggered. The Interflow includes the application used in the connection (appid_name), the source host (srcip_host), and the source reputation (srcip_reputation).

Unsupervised

Y

Command Anomaly

A command has been executed an anomalously large number of times compared to its typical executions or those of other commands. Investigate the command and the user to determine if this is expected.

XDR Kill Chain

  • Kill Chain Stage: Persistent Foothold

  • Tactic: Execution (TA0002 )

  • Technique: Command and Scripting Interpreter (T1059 )

  • Tags: []

Event Name

The xdr_event.name for this alert type in the Interflow data is command_anomaly.

Severity

15

Key Fields and Relevant Data Points

  • command — command executed  
  • actual — actual number of executions in the period
  • typical — typical number of executions in the period
  • cwd — current working directory from which the command executed
  • hostip — host from which the command was run
  • hostip_host — host name
  • username — user name who ran the command

Use Case with Data Points

The number of times a command (command) has been executed is calculated periodically. If the volume (actual) is much larger than the typical volume (typical) of the command or other commands in any period, an alert is triggered. The Interflow includes the directory from which the command was executed (cwd), the host and source IP addresses (hostip and srcip) from which the command was executed, and the name of the user who ran the command (username).

Unsupervised

Y

Cryptojacking

An unauthorized coin miner used a computer to mine cryptocurrency. Consider blocking the source IP address.

XDR Kill Chain

  • Kill Chain Stage: Exfiltration & Impact

  • Tactic: Impact (TA0040 )

  • Technique: Resource Hijacking (T1496 )

  • Tags: [Network Traffic Analysis]

Event Name

The xdr_event.name for this alert type in the Interflow data is cryptojacking.

Severity

70

Key Fields and Relevant Data Points

  • ids.signature — IDS signature  
  • srcip — source IP address of the cryptojacking action 
  • dstip — destination IP address of the cryptojacking action 
  • srcip_reputation — source reputation
  • srcip_host — source host name
  • dstip_reputation — destination reputation
  • dstip_host — destination host name

Use Case with Data Points

If an unauthorized coin miner is detected by IDS, an alert is triggered. A sample Interflow includes the IDS signature (ids.signature), source IP address (srcip), source reputation (srcip_reputation), source host (srcip_host), destination IP address (dstip), destination reputation (dstip_reputation), and destination host (dstip_host).

Analytics

N

CylanceOPTICS: XDR Anomaly

On a specific device, a rarely seen or an anomalously large number of CylanceOPTICS endpoint log records has been observed, compared to the typical number in a measured interval or has been observed after several days of silence.

XDR Kill Chain

  • Kill Chain Stage: Persistent Foothold

  • Tactic: XDR EBA (XTA0001)

  • Technique: XDR Anomaly (XT1000)

  • Tags: []

Event Name

The xdr_event.name for this alert type in the Interflow data is cylance_edr_anomaly.

Severity

30

Key Fields and Relevant Data Points

  • event.description — description of the detection rule  
  • host.name — device name
  • actual — actual number of log records in the period
  • typical — typical number of log records generated on the device

Use Case with Data Points

The number of occurrences of CylanceOPTICS log records (event.provider) is calculated periodically. If this category occurs (actual) much more often compared to its history (typical) or a rarely seen type of event is generated, an alert is triggered. The Interflow includes information such as the process name (process.name), parent process name (process.parent.name), and description (event.description).

Unsupervised

Y

Data Ingestion Volume Anomaly

A sensor is sending an anomalously high or low volume of data, compared to its typical volume. Check the sensor. A low volume could indicate a sensor failure or other problems. For a high volume, determine the cause of the increase.

XDR Kill Chain

  • Kill Chain Stage: Initial Attempts

  • Tactic: XDR SBA (XTA0003)

  • Technique: XDR Bytes Anomaly (XT3001)

  • Tags: [Network Traffic Analysis]

Event Name

The xdr_event.name for this alert type in the Interflow data is ade_outbytes_anomaly.

Severity

10

Key Fields and Relevant Data Points

  • engid — sensor ID 
  • engid_name — sensor name
  • actual — actual volume of data in the period
  • typical — typical difference in data volume between this period and the previous period

Use Case with Data Points

The data ingestion volume of every data sensor with sensor id (engid) and sensor name (engid_name) is calculated periodically. If one of the following conditions is met, the anomaly is triggered:

  • A moving window is used to record data ingestion volume. If the time window can be divided into two sub windows and the metric values of these two sub windows show large deviation

  • The ingestion volume is anomalously high compared to its own history

  • The ingestion volume is anomalously low compared to its history and it keeps being low for a relatively longer period

A sample Interflow includes the sensor ID (engid) and sensor name (engid_name).

Unsupervised

Y

DGA

A host is using a potential Domain Generation Algorithm (DGA). If the target domain is a malicious domain, the host might be compromised. Investigate the DGA domains and the host.

XDR Kill Chain

  • Kill Chain Stage: Persistent Foothold

  • Tactic: Command and Control (TA0011 )

  • Technique: Dynamic Resolution (T1568 )

  • Tags: [Network Traffic Analysis]

Event Name

The xdr_event.name for this alert type in the Interflow data is dga_resolvable.

Severity

75

Key Fields and Relevant Data Points

  • srcip — source IP address of the host that sends the DGA queries  
  • metadata.request.effective_tld — effective top-level domain of the DNS query  
  • srcip_host — source host name
  • is_dga — flag marking whether or not the DNS query is a DGA query
  • actual — number of DGA domains the host has queried

Use Case with Data Points

Whenever a host (srcip) sends a DNS query (appid_name: dns) and the DNS server returns a non-existent domain (NXDOMAIN) response (metadata.response.reply_code), the NX domain query counter for the host is increased. We reset the counter if no NX domain queries are observed for a period of time. When the counter reaches a certain threshold, the host is monitored. When monitored, we run the FQDNs of all DNS queries (metadata.response.query) sent by this host through domain generation analytics to determine whether the domain's entropy indicates a DGA anomaly. If so, we mark the DNS record (is_dga). If the DNS query gets a response with valid resolved IP addresses (metadata.response.resolved_ips), we call it a resolvable query, otherwise we call it a non-resolvable query.

If a monitored host (srcip) sends a resolvable DGA query (is_dga: yes_resolvable), we check the effective top-level domain (metadata.response.effective_tld). If the same host (srcip) previously sent non-resolvable DGA queries (is_dga: yes) with the same effective top-level domain (metadata.response.effective_tld), the host is considered to have a high risk of being compromised and performing C&C with DGA. The Interflow includes the source host (srcip), DNS query (metadata.response.query), query effective top-level domain (metadata.response.effective_tld), and DGA flag (is_dga).

Supervised

N

DHCP Server Anomaly

A new DHCP server appeared in the network. This could be a hacker attempting to steer traffic. Investigate and consider telling employees to avoid this server.

XDR Kill Chain

  • Kill Chain Stage: Exploration

  • Tactic: [Internal] XDR NBA (XTA0002)

  • Technique: XDR Server Anomaly (XT2007)

  • Tags: [Internal]

Event Name

The xdr_event.name for this alert type in the Interflow data is dhcp_anomaly.

Severity

20

Key Fields and Relevant Data Points

  • metadata.response.server_ip — IP address of the anomalous DHCP server  
  • dstip — IP address of the anomalous DHCP destination 
  • engid — sensor that reported the DHCP traffic
  • srcip_host — host name that visited the suspicious DHCP server
  • srcip_geo.countryName — country name of the source that visited the suspicious DHCP server

Use Case with Data Points

If a DHCP server that has never been seen before appears in the network, an alert is triggered. The Interflow includes the destination IP address (dstip), destination host (dstip_host), source host (srcip_host), and source country (srcip_geo.countryName).

Analytics

N

DNS Tunneling Anomaly

An anomalously large number of connections tunneling high-entropy traffic through DNS were made. This can indicate data exfiltration. Investigate the tunnel and source host. If malicious, block the source host.

XDR Kill Chain

  • Kill Chain Stage: Exfiltration & Impact

  • Tactic: Exfiltration (TA0010 )

  • Technique: Exfiltration Over Alternative Protocol (T1048 )

  • Tags: []

Event Name

The xdr_event.name for this alert type in the Interflow data is dns_tunnel.

Severity

98

Key Fields and Relevant Data Points

  • metadata.request.effective_tld — effective top-level domain, such as yahoo.com  
  • srcip — source IP address  
  • srcip_host — host name of corresponding source IP address
  • dstip_host — host name of corresponding destination IP address
  • metadata.request.query — DNS query
  • actual — actual number of bytes transmitted through the tunnel in the period
  • typical — typical number of bytes transmitted through a tunnel in the period
  • total_entropy — total entropy (information density) sent by the DNS tunnel
  • query_count — number of queries sent by the DNS tunnel

Use Case with Data Points

The DNS queries (metadata.requests.query) for each DNS tunnel (comprising the source host (srcip_host), destination host (dstip), and top-level domain (effective_tld)) are analyzed periodically. If a DNS tunnel has sent anomalously more entropy (total_entropy) and bytes (actual) than is normal (typical) in any period, an alert is triggered. The number of queries sent (query_count) is also considered.

Supervised

N

Emerging Threat

An emerging threat has been observed. Investigate the IP address and consider blocking.

XDR Kill Chain

  • Kill Chain Stage: Persistent Foothold

  • Tactic: XDR Intel (XTA0005)

  • Technique: XDR Emerging Threat (XT5003)

  • Tags: []

Event Name

The xdr_event.name for this alert type in the Interflow data is emerging_threat.

Severity

80

Key Fields and Relevant Data Points

  • srcip — source IP address marked as an emerging threat  
  • dstip — destination IP address marked as an emerging threat  
  • url_list — URL marked as an emerging threat  
  • domain_list — domain marked as an emerging threat  
  • srcip_host — host name of corresponding source IP address
  • dstip_host — host name of corresponding destination IP address

Use Case with Data Points

Stellar Cyber monitors traffic for emerging threats. An alert is triggered if emerging threats are observed in any of the following:

  • Source IP address (srcip)
  • Destination IP address (dstip)
  • URL (url_list)
  • Domain (domain_list)

Note that only one of these is needed to trigger the alert. So, although the Interflow includes the source IP address (srcip), destination IP address (dstip), URL (url_list), and domain (domain_list), not all the values may be populated, depending on the nature of the observed threat.

Analytics

N

Encoded PowerShell

A Windows host executed an encoded PowerShell script. Investigate the script contents to see if it is malicious. If so, consider quarantining the host.

XDR Kill Chain

  • Kill Chain Stage: Persistent Foothold

  • Tactic: Execution (TA0002 )

  • Technique: Command and Scripting Interpreter (T1059 )

  • Tags: []

Event Name

The xdr_event.name for this alert type in the Interflow data is encoded_powershell.

Severity

80

Key Fields and Relevant Data Points

  • srcip — source IP address  
  • hostip — IP address of the Windows host
  • hostip_host — host name
  • event_data.ContextInfo — PowerShell script context
  • event_data.Payload — PowerShell script payload

Use Case with Data Points

If a Windows host (srcip) executes a PowerShell script whose context (event_data.ContextInfo) includes flags that indicate encoding or obfuscation of the script, an alert is triggered. The Interflow includes the IP address of the Windows host (srcip), the script context (event_data.ContextInfo), and script payload (event_data.Payload).

Analytics

N

Encrypted C&C

A connection to or from known command and control servers was observed in encrypted traffic. Consider blocking the source IP address.

XDR Kill Chain

  • Kill Chain Stage: Persistent Foothold

  • Tactic: Command and Control (TA0011 )

  • Technique: Encrypted Channel (T1573 )

  • Tags: [Network Traffic Analysis]

Event Name

The xdr_event.name for this alert type in the Interflow data is ssl_certificate.

Severity

75

Key Fields and Relevant Data Points

  • srcip — source IP address of the connection  
  • dstip — destination IP address of the connection  
  • srcip_host — host name of corresponding source IP address
  • srcip_geo.countryName — source country of the connection
  • dstip_host — host name of corresponding destination IP address
  • dstip_geo.countryName — destination country of the connection

Use Case with Data Points

If known command and control servers are detected on either side of a connection with encrypted traffic, an alert is triggered. The Interflow includes the source IP address (srcip), source host (srcip_host), source country (srcip_geo.countryName), destination IP address (dstip), destination host (dstip_host), and destination country (dstip_geo.countryName).

Analytics

N

Exploited C&C Connection

An exploited host with vulnerabilities initiated a connection to the exploit attacker, which could indicate the host being compromised and performing C&C activities. See if the exploit was successful. Check the source host, and consider blocking.

XDR Kill Chain

  • Kill Chain Stage: Initial Attempts

  • Tactic: [External] XDR NBA (XTA0002)

  • Technique: XDR Command and Control Connection Exploitation (XT2014)

  • Tags: [Network Traffic Analysis]

Event Name

The xdr_event.name for this alert type in the Interflow data is exploit_attempt_correlation.

Severity

75

Key Fields and Relevant Data Points

  • tenant_id — tenant ID
  • exploit_id — ID of the original exploit event
  • seen_traffic_id — ID of the original Interflow traffic record
  • srcip (of exploit event) — IP address of the attacker (correlation_info.srcip)
  • dstip (of exploit event) — IP address of the target host (correlation_info.dstip)
  • srcip (of traffic record) — IP address of the target host (correlation_info.srcip)
  • dstip (of traffic record) — IP address of the attacker (correlation_info.dstip)

Use Case with Data Points

Two events are involved in this alert type. In the first event, an attacker (srcip) with the IP address A is performing an exploit against a target (dstip) with the IP address B. If, following that event, an Interflow traffic record is observed where the target host (srcip) with IP address B initiates a network connection to the attacker (dstip) whose IP address is A, an alert is triggered.

When an alert is triggered a new correlation event is generated. The Interflow of the correlation event includes the reference ID of the exploit event (exploit_id), the reference ID of the traffic record (seen_traffic_id), the IP address of the attacker (correlation_info.srcip of the exploit event or correlation_info.dstip of the traffic record), the IP address of the victim (correlation_info.dstip of the exploit event or correlation_info.srcip of the traffic record).

Analytics

N

External Account Login Failure Anomaly

An anomalously large number of user login failures was observed for an account. Check with the user.

This alert type has a relatively long detection delay of up to 40 minutes because it waits for login events from high latency data sources and is sensitive to the event order of user logins.

XDR Kill Chain

  • Kill Chain Stage: Initial Attempts

  • Tactic: [External] Credential Access (TA0006 )

  • Technique: Brute Force (T1110 )

  • Tags: [External]

Event Name

The xdr_event.name for this alert type in the Interflow data is external_cloud_account_login_failure.

Severity

45

Key Fields and Relevant Data Points

  • srcip_usersid — cloud account user ID  
  • scrip_username — cloud account user name 
  • event_summary.total_failed — number of failed logins in the period
  • event_summary.total_successful — number of successful logins in the period
  • event_summary.total_fail_ratio — percent of failed logins in the period, which is: event_summary.total_failed / (event_summary.total_failed + event_summary.total_successful)
  • weighted_anomaly_score — net score based on weighted rating of successful versus failed attempts (scanning, login, or other). Scores greater than upper threshold are potentially malicious and less than lower threshold are benign.
  • srcip_host — host name of corresponding source IP address
  • login_type — type of login
  • srcip_reputation — source reputation

Use Case with Data Points

Login failures and successes are calculated periodically for every account (srcip_usersid). If the number of failures is significantly larger than the number of successes, an alert is triggered. A sample Interflow includes the login type (login_type), source host (srcip_host), and source reputation (srcip_reputation).

...

Stellar Cyber reports both internal and external versions of some alerts, with different analysis and recommended actions for each. Similarly, IDS signatures report the direction of data flow as inbound or outbound. Use the following as a guide for these concepts:

  • Addresses with a srcip_type or dstip_type of private are identified as internal. All other values are identified as external (when applicable; not all alerts have unique analytics for internal/external).
  • Communications between hosts where srcip_type and dstip_type are both private are considered internal communications.
  • When an anomaly is observed on an internal communication, the attack is considered to be internal.
  • Stellar Cyber always sets the srcip in the Interflow record as the initiating IP address of an event. Note that IDS signatures, which are reported with relevant alerts, instead list addresses based on the direction of data flow, not the initiating address. So an INBOUND data flow may show the dstip as the source address and the srcip as the destination address, even though the srcip was the initiator of the request. Use INBOUND and OUTBOUND information in the signature to understand the direction of data flow, together with Stellar Cyber’s Interflow record of srcip and dstip to understand which address initiated the threat event.

Unsupervised

N

External Brute-Forced Successful User Login

A successful login was observed from an IP address that had previously seen a large number of login failures, or a successful login to a user account was observed from another IP address or IP addresses that had previously seen a large number of login failures to that account. Check with the user.

This alert type has two subtypes:

This alert type has a relatively long detection delay of up to 40 minutes because it waits for login events from high latency data sources and is sensitive to the event order of user logins.

XDR Kill Chain

  • Kill Chain Stage: Initial Attempts

  • Tactic: [External] Credential Access (TA0006 )

  • Technique: Brute Force (T1110 )

  • Tags: [External]

Event Name

The xdr_event.name for this alert type in the Interflow data is external_user_success_brute_forcer.

Severity

90

Alert Subtype: Source IP-Based

The source IP-based alert subtype has the same XDR Kill Chain and Event Name as the user ID-based alert subtype, but differs in the Key Fields and Relevant Data Points and Use Case with Data Points.

Key Fields and Relevant Data Points

  • srcip — source IP address  
  • srcip_usersid — Windows SID associated with the source IP address
  • srcip_host — source host name
  • srcip_reputation — source reputation
  • source_geo.countryName — source country
  • dstip_host — destination host name
  • login_type — type of login
  • username — user name
  • related_alert._id — link to the related External User Login Failure Anomaly

Use Case with Data Points

The login records are checked for every external source IP address (srcip). An alert is triggered if that IP address:

  1. Has so many failed login attempts that it triggered the External User Login Failure Anomaly, and
  2. Had a successful login

A sample Interflow includes the source IP address (srcip), login type (login_type), source host (srcip_host), source reputation (srcip_reputation), source country (srcip_geo.countryName), and user name (username).

Alert Subtype: User ID-Based

The user ID-based alert subtype has the same XDR Kill Chain and Event Name as the source IP-based alert subtype, but differs in the Key Fields and Relevant Data Points and Use Case with Data Points.

Key Fields and Relevant Data Points

  • srcip_usersid — Windows SID associated with the source IP address 
  • srcip — source IP address
  • srcip_host — source host name
  • srcip_reputation — source reputation
  • source_geo.countryName — source country
  • dstip_host — destination host name
  • login_type — type of login
  • username — user name
  • related_alert._id — link to the related External Account Login Failure Anomaly

Use Case with Data Points

The login records to a user account (srcip_usersid) are checked for every external source IP address (srcip). An alert is triggered if that user account:

  1. Has so many failed login attempts that it triggered the External Account Login Failure Anomaly, and

  2. Had a successful login

A sample Interflow includes the source IP address (srcip), login type (login_type), source host (srcip_host), source reputation (srcip_reputation), source country (srcip_geo.countryName), and user name (username).

...

Stellar Cyber reports both internal and external versions of some alerts, with different analysis and recommended actions for each. Similarly, IDS signatures report the direction of data flow as inbound or outbound. Use the following as a guide for these concepts:

  • Addresses with a srcip_type or dstip_type of private are identified as internal. All other values are identified as external (when applicable; not all alerts have unique analytics for internal/external).
  • Communications between hosts where srcip_type and dstip_type are both private are considered internal communications.
  • When an anomaly is observed on an internal communication, the attack is considered to be internal.
  • Stellar Cyber always sets the srcip in the Interflow record as the initiating IP address of an event. Note that IDS signatures, which are reported with relevant alerts, instead list addresses based on the direction of data flow, not the initiating address. So an INBOUND data flow may show the dstip as the source address and the srcip as the destination address, even though the srcip was the initiator of the request. Use INBOUND and OUTBOUND information in the signature to understand the direction of data flow, together with Stellar Cyber’s Interflow record of srcip and dstip to understand which address initiated the threat event.

Unsupervised+Analytics

N

External Credential Stuffing

An anomalously large amount of username/password testing was observed on AWS, Okta, or Windows. Check the activity after successful logins, and consider blocking the source IP addresses.

XDR Kill Chain

  • Kill Chain Stage: Initial Attempts

  • Tactic: [External] Credential Access (TA0006 )

  • Technique: Brute Force (T1110 )

  • Tags: [External]

Event Name

The xdr_event.name for this alert type in the Interflow data is external_credential_stuffing.

Severity

50

Key Fields and Relevant Data Points

  • msg_class — name of the service: cloudtrail for AWS, okta for Okta, Microsoft-Windows-Security-Auditing for Windows  
  • service_id — specific account ID of a service  
  • login_failure_rate — rate of login failures per minute in the period
  • unknown_users_rate — rate of unknown user names per minute in the period
  • unknown_users_to_login_failures — ratio of unknown user names to login failures in the period
  • suspicious_ips — suspicious source IP addresses (up to 100)
  • possible_breached_ips — list of malicious IPs that may have successful breach activities

Use Case with Data Points

External credential stuffing is the constant testing of username/password combinations on the AWS, Okta, or Windows authentication functions. Login activity is monitored and if the number of failed logins is larger than normal for that service, an alert is triggered. The Interflow includes the service (msg_class), tenant's account ID on that service (service_id), suspicious source IP address (suspicious_ips), login failure rate (login_failure_rate), unknown user rate (unknown_users_rate), the ratio of unknown users to login failures (unknown_users_to_login_failures), and a list of source IP addresses that might have suspicious activities and should be investigated (possible_breached_ips).

...

Stellar Cyber reports both internal and external versions of some alerts, with different analysis and recommended actions for each. Similarly, IDS signatures report the direction of data flow as inbound or outbound. Use the following as a guide for these concepts:

  • Addresses with a srcip_type or dstip_type of private are identified as internal. All other values are identified as external (when applicable; not all alerts have unique analytics for internal/external).
  • Communications between hosts where srcip_type and dstip_type are both private are considered internal communications.
  • When an anomaly is observed on an internal communication, the attack is considered to be internal.
  • Stellar Cyber always sets the srcip in the Interflow record as the initiating IP address of an event. Note that IDS signatures, which are reported with relevant alerts, instead list addresses based on the direction of data flow, not the initiating address. So an INBOUND data flow may show the dstip as the source address and the srcip as the destination address, even though the srcip was the initiator of the request. Use INBOUND and OUTBOUND information in the signature to understand the direction of data flow, together with Stellar Cyber’s Interflow record of srcip and dstip to understand which address initiated the threat event.

Unsupervised

N

External Exploited Vulnerability

A host with a vulnerability discovered by a security scanning tool was exploited by an attack on that same vulnerability, indicating a high probability of success. Check the target to see if it was compromised.

XDR Kill Chain

  • Kill Chain Stage: Initial Attempts

  • Tactic: [External] XDR NBA (XTA0002)

  • Technique: XDR Exploited Vulnerability (XT2015)

  • Tags: [External; Network Traffic Analysis]

Event Name

The xdr_event.name for this alert type in the Interflow data is external_vuln_exploit_correlation.

Severity

75

Key Fields and Relevant Data Points

  • tenantid — tenant ID
  • vulnerability_id — ID of the original security scan result
  • ids_event_id — ID of the original IDS exploit event
  • srcip (of security scan result) — IP address of the target correlation_info.srcip
  • dstip (of IDS event) — IP address of the target (correlation_info.dstip)
  • srcip (of IDS event) — IP address of the attacker (correlation_info.srcip)
  • correlation_info.vulnerability.cve — CVE associated with the reported vulnerability
  • correlation_info.ids.cve — CVE the attacker used to exploit the host

Use Case with Data Points

An attacker (srcip) with IP address A is performing an exploit against a target (dstip) with internal IP address B using a vulnerability (ids.cve) with CVE x. If any security scanning tool found the target (srcip) with IP address B to have a vulnerability (vulnerability.cve) with CVE x, an alert is triggered.

When an alert is triggered, a new correlation event is generated. The Interflow of the correlation event includes the ID of the IDS exploit event (ids_event_id), the ID of the security scan record (vulnerability_id), the IP address of the attacker (correlation_info.srcip of the IDS event), the IP address of the victim (correlation_info.dstip of the IDS event or correlation_info.srcip of the security scan record), and the CVE that was used in the exploit (correlation_info.vulnerability.cve and correlation_info.ids.cve).

...

Stellar Cyber reports both internal and external versions of some alerts, with different analysis and recommended actions for each. Similarly, IDS signatures report the direction of data flow as inbound or outbound. Use the following as a guide for these concepts:

  • Addresses with a srcip_type or dstip_type of private are identified as internal. All other values are identified as external (when applicable; not all alerts have unique analytics for internal/external).
  • Communications between hosts where srcip_type and dstip_type are both private are considered internal communications.
  • When an anomaly is observed on an internal communication, the attack is considered to be internal.
  • Stellar Cyber always sets the srcip in the Interflow record as the initiating IP address of an event. Note that IDS signatures, which are reported with relevant alerts, instead list addresses based on the direction of data flow, not the initiating address. So an INBOUND data flow may show the dstip as the source address and the srcip as the destination address, even though the srcip was the initiator of the request. Use INBOUND and OUTBOUND information in the signature to understand the direction of data flow, together with Stellar Cyber’s Interflow record of srcip and dstip to understand which address initiated the threat event.

Analytics

N

External Firewall Denial Anomaly

A source host had actions blocked by a firewall too many times. Investigate the firewall rules that were violated. If suspicious, block the source IP address.

XDR Kill Chain

Kill Chain Stage: Initial Attempts

Tactic: [External] XDR NBA (XTA0002)

Technique: XDR Firewall Anomaly (XT2002)

Tags: [External; Network Traffic Analysis; Firewall Anomalies]

Event Name

The xdr_event.name for this alert type in the Interflow data is external_fw_action.

Severity

40

Key Fields and Relevant Data Points

  • srcip_host — source host IP address  
  • srcip — source host IP address
  • actual — actual number of firewall denials in the period
  • typical — typical number of firewall denials in the period
  • dstip_host — host name of corresponding destination IP address
  • dev_name — name of the firewall
  • engid_name — name of the sensor

Use Case with Data Points

The number of firewall denials for every source IP address (srcip) is calculated periodically. If a source IP address’s number of firewall denials (actual) is much larger than the historical count (typical) of all IP addresses, an alert is triggered. The Interflow includes the name of the firewall (dev_name), the name of the sensor (engid_name), and the destination host (dstip_host).

...

Stellar Cyber reports both internal and external versions of some alerts, with different analysis and recommended actions for each. Similarly, IDS signatures report the direction of data flow as inbound or outbound. Use the following as a guide for these concepts:

  • Addresses with a srcip_type or dstip_type of private are identified as internal. All other values are identified as external (when applicable; not all alerts have unique analytics for internal/external).
  • Communications between hosts where srcip_type and dstip_type are both private are considered internal communications.
  • When an anomaly is observed on an internal communication, the attack is considered to be internal.
  • Stellar Cyber always sets the srcip in the Interflow record as the initiating IP address of an event. Note that IDS signatures, which are reported with relevant alerts, instead list addresses based on the direction of data flow, not the initiating address. So an INBOUND data flow may show the dstip as the source address and the srcip as the destination address, even though the srcip was the initiator of the request. Use INBOUND and OUTBOUND information in the signature to understand the direction of data flow, together with Stellar Cyber’s Interflow record of srcip and dstip to understand which address initiated the threat event.

Unsupervised

Y

External Firewall Policy Anomaly

A rarely triggered firewall policy has been violated. Investigate that policy and track down the violation.

XDR Kill Chain

  • Kill Chain Stage: Initial Attempts

  • Tactic: [External] XDR NBA (XTA0002)

  • Technique: XDR Firewall Anomaly (XT2002)

  • Tags: [External; Network Traffic Analysis;Firewall Anomalies]

Event Name

The xdr_event.name for this alert type in the Interflow data is external_fw_policy_id.

Severity

20

Key Fields and Relevant Data Points

  • fw_policy_id — ID of the violated firewall policy  
  • days_silent — number of days since this firewall policy was last seen
  • srcip_host — host name of corresponding source IP address
  • dstip_host — host name of corresponding destination IP address
  • dev_name — device name
  • dev_type — device type
  • engid_name — sensor name

Use Case with Data Points

A firewall policy violation (fw_policy_id), which is raised by a device (dev_name and dev_type) and captured by a sensor (engid_name), shows never seen or very rare (days_silent) traffic between a host (srcip_host) and another host (dstip_host). This violation will trigger an alert.

...

Stellar Cyber reports both internal and external versions of some alerts, with different analysis and recommended actions for each. Similarly, IDS signatures report the direction of data flow as inbound or outbound. Use the following as a guide for these concepts:

  • Addresses with a srcip_type or dstip_type of private are identified as internal. All other values are identified as external (when applicable; not all alerts have unique analytics for internal/external).
  • Communications between hosts where srcip_type and dstip_type are both private are considered internal communications.
  • When an anomaly is observed on an internal communication, the attack is considered to be internal.
  • Stellar Cyber always sets the srcip in the Interflow record as the initiating IP address of an event. Note that IDS signatures, which are reported with relevant alerts, instead list addresses based on the direction of data flow, not the initiating address. So an INBOUND data flow may show the dstip as the source address and the srcip as the destination address, even though the srcip was the initiator of the request. Use INBOUND and OUTBOUND information in the signature to understand the direction of data flow, together with Stellar Cyber’s Interflow record of srcip and dstip to understand which address initiated the threat event.

Unsupervised

Y

External Handshake Failure

There were too many handshake failures between two hosts, which might indicate port scanning. Check the source host to see if this was expected and, if not, consider blocking the host.

XDR Kill Chain

  • Kill Chain Stage: Initial Attempts

  • Tactic: [External] Reconnaissance (TA0043 )

  • Technique: Active Scanning (T1595 )

  • Tags: [External; Network Traffic Analysis]

Event Name

The xdr_event.name for this alert type in the Interflow data is external_handshake_failure.

Severity

10

Key Fields and Relevant Data Points

  • srcip — source IP address of the host with the handshake failures 
  • srcip_host — source host name
  • dstip — destination IP address of the host with the handshake failures 
  • dstip_host — destination host name
  • timestamp — when the scan happened

Use Case with Data Points

If a host (srcip) scans across many ports on another host (dstip), an alert is triggered. The Interflow includes the IP address of the potential attacker (srcip), the IP address of the victim (dstip), a special message flag (msgtyp), and when the scan happened (timestamp).

...

Stellar Cyber reports both internal and external versions of some alerts, with different analysis and recommended actions for each. Similarly, IDS signatures report the direction of data flow as inbound or outbound. Use the following as a guide for these concepts:

  • Addresses with a srcip_type or dstip_type of private are identified as internal. All other values are identified as external (when applicable; not all alerts have unique analytics for internal/external).
  • Communications between hosts where srcip_type and dstip_type are both private are considered internal communications.
  • When an anomaly is observed on an internal communication, the attack is considered to be internal.
  • Stellar Cyber always sets the srcip in the Interflow record as the initiating IP address of an event. Note that IDS signatures, which are reported with relevant alerts, instead list addresses based on the direction of data flow, not the initiating address. So an INBOUND data flow may show the dstip as the source address and the srcip as the destination address, even though the srcip was the initiator of the request. Use INBOUND and OUTBOUND information in the signature to understand the direction of data flow, together with Stellar Cyber’s Interflow record of srcip and dstip to understand which address initiated the threat event.

Analytics

N

External IDS Signature Spike

A source IP address transmitted an anomalous number of different IDS signatures. Typically, this indicates host penetration or vulnerability scanning.

XDR Kill Chain

  • Kill Chain Stage: Initial Attempts

  • Tactic: Initial Access (TA0001 )

  • Technique: Exploit Public-Facing Application (T1190 )

  • Tags: [External; Network Traffic Analysis]

Event Name

The xdr_event.name for this alert type in the Interflow data is external_ids_signature_spike.

Severity

50

Key Fields and Relevant Data Points

  • srcip — source IP address 
  • ids_signatures_summarize — summarized IDS signatures of the exploit
  • srcip_host — source host name
  • actual — actual number of unique IDS signatures in the period, with critical IDS signatures counted as 2, high counted as 1, low counted as 0.5, and others counted as 1
  • typical — typical number of unique IDS signatures from the source IP address, with critical IDS signatures counted as 2, high counted as 1, low counted as 0.5, and others counted as 1

Use Case with Data Points

The number of unique IDS signatures (ids.signature), weighted by their severity (ids.severity), are calculated periodically. If many different exploits with unique IDS signatures are observed, an alert is triggered. The Interflow includes a source (srcip), timestamp, an accumulated severity of IDS signatures (actual), the usual accumulated severity of IDS signatures (typical), and a sampling of the IDS signatures used in the attack (ids_signatures_summarize).

...

Stellar Cyber reports both internal and external versions of some alerts, with different analysis and recommended actions for each. Similarly, IDS signatures report the direction of data flow as inbound or outbound. Use the following as a guide for these concepts:

  • Addresses with a srcip_type or dstip_type of private are identified as internal. All other values are identified as external (when applicable; not all alerts have unique analytics for internal/external).
  • Communications between hosts where srcip_type and dstip_type are both private are considered internal communications.
  • When an anomaly is observed on an internal communication, the attack is considered to be internal.
  • Stellar Cyber always sets the srcip in the Interflow record as the initiating IP address of an event. Note that IDS signatures, which are reported with relevant alerts, instead list addresses based on the direction of data flow, not the initiating address. So an INBOUND data flow may show the dstip as the source address and the srcip as the destination address, even though the srcip was the initiator of the request. Use INBOUND and OUTBOUND information in the signature to understand the direction of data flow, together with Stellar Cyber’s Interflow record of srcip and dstip to understand which address initiated the threat event.

Unsupervised

Y

External IP / Port Scan Anomaly

A host has either generated an anomalous number of connections compared to the typical amount, or has triggered an anomalous number of connection failure responses, in the measured interval. This can indicate that an attacker is scanning for computers or ports to exploit.

This alert type has two subtypes:

Alert Subtype: Connection Failure Anomaly (Sensor Traffic)

XDR Kill Chain

  • Kill Chain Stage: Initial Attempts

  • Tactic: [External] Reconnaissance (TA0043 )

  • Technique: Active Scanning (T1595 )

  • Tags: [External; Network Traffic Analysis]

Event Name

The xdr_event.name for this alert type in the Interflow data is external_port_scan.

Severity

10

Key Fields and Relevant Data Points

  • srcip — source IP address  
  • num_failed — unique number of (destination IP and destination port) tuples that respond with failed status
  • num_successful — unique number of (destination IP and destination port) tuples that respond with success status
  • percent_failed — percent of unique (destination IP and destination port) tuples that respond with failed status
  • weighted_anomaly_score — net score based on weighted rating of successful versus failed attempts (scanning, login, or other). Scores greater than upper threshold are potentially malicious and less than lower threshold are benign.
  • srcip_host — host name of corresponding source IP address
  • dstip_host — host name of corresponding destination IP address
  • appid_name — application name

Use Case with Data Points

For every unique triplet (source IP address, destination IP address, and destination port) browsed by each source IP address (srcip), the number of response failures and successes is calculated periodically. If the number of failures is significantly larger than the number of successes, an alert is triggered. The Interflow includes the source host (srcip_host), destination host (dstip_host), and application name (appid_name).

Considering that a lateral scan (private to private) is more sensitive than a non-lateral scan, this alert type is divided into two parts. One focuses on lateral scan analysis, the other focuses on non-lateral scan analysis. The mechanism remains the same as before, with the trigger condition for lateral scan alert being more sensitive than non-lateral one.

Validation / Remediation

If the source IP address is internal targeting an external address, check with the user if they are aware of the activity or if they are authorized to perform the activity. Inform the user's supervisor if the activity is unauthorized.

If the source IP address is external targeting any addresses, check the reputation of the source IP address as in known malicious/scanner.

Potential False Positives

Some legitimate activities such as vulnerability scans or penetration testing may trigger this alert type, if from an external IP address to an internal IP address.

Alert Subtype: Connection Spike Anomaly (Firewall / Windows Traffic)

XDR Kill Chain

  • Kill Chain Stage: Initial Attempts

  • Tactic: [External] Reconnaissance (TA0043 )

  • Technique: Active Scanning (T1595 )

  • Tags: [External; Network Traffic Analysis]

Event Name

The xdr_event.name for this alert type in the Interflow data is external_port_scan_tsa.

Severity

10

Key Fields and Relevant Data Points

  • srcip — source IP address  
  • actual — actual number of connections to the destination IP address in the period
  • typical — typical number of connections to the destination IP address
  • srcip_host — host name of corresponding source IP address
  • dstip_host — host name of corresponding destination IP address
  • appid_name — application name

Use Case with Data Points

For every unique (destination IP address and destination port) browsed by each source IP address (srcip), the number of response failures and successes and the number of total data volume are calculated periodically. If the total data volume is significantly larger than the typical number, an alert is triggered. The Interflow includes the source host (srcip_host), destination host (dstip_host), and application name (appid_name).

Considering that a lateral scan (private to private) is more sensitive than a non-lateral scan, this alert type is divided into two parts. One focuses on lateral scan analysis, the other focuses on non-lateral scan analysis. The mechanism remains the same as before, with the trigger condition for lateral scan alert being more sensitive than non-lateral one.

Validation / Remediation

If the source IP address is internal targeting an external address, check with the user if they are aware of the activity or if they are authorized to perform the activity. Inform the user's supervisor if the activity is unauthorized.

If the source IP address is external targeting any addresses, check the reputation of the source IP address as in known malicious/scanner.

Potential False Positives

Some legitimate activities such as vulnerability scans or penetration testing may trigger this alert type, if from an external IP address to an internal IP address.

...

Stellar Cyber reports both internal and external versions of some alerts, with different analysis and recommended actions for each. Similarly, IDS signatures report the direction of data flow as inbound or outbound. Use the following as a guide for these concepts:

  • Addresses with a srcip_type or dstip_type of private are identified as internal. All other values are identified as external (when applicable; not all alerts have unique analytics for internal/external).
  • Communications between hosts where srcip_type and dstip_type are both private are considered internal communications.
  • When an anomaly is observed on an internal communication, the attack is considered to be internal.
  • Stellar Cyber always sets the srcip in the Interflow record as the initiating IP address of an event. Note that IDS signatures, which are reported with relevant alerts, instead list addresses based on the direction of data flow, not the initiating address. So an INBOUND data flow may show the dstip as the source address and the srcip as the destination address, even though the srcip was the initiator of the request. Use INBOUND and OUTBOUND information in the signature to understand the direction of data flow, together with Stellar Cyber’s Interflow record of srcip and dstip to understand which address initiated the threat event.

Unsupervised

Y

External Non-Standard Port Anomaly

An application had an anomalously large number of connections or a rarely seen connection on non-standard ports. Check the application to be sure this is benign.

XDR Kill Chain

  • Kill Chain Stage: Persistent Foothold

  • Tactic: [External] Command and Control (TA0011 )

  • Technique: Non-Standard Port (T1571 )

  • Tags: [External; Network Traffic Analysis]

Event Name

The xdr_event.name for this alert type in the Interflow data is external_non_std_port_anomaly.

Severity

15

Key Fields and Relevant Data Points

  • dstip — destination IP address  
  • dstport — destination port  
  • appid — application ID  
  • days_silent — number of days since the application was last seen
  • appid_name — application name
  • dstip_host — host name of corresponding destination IP address
  • actual — actual number of connections in the period
  • typical — typical number of connections in the period

Use Case with Data Points

The number of connections for an application (dst_ip + dstport + appid) is calculated periodically. If a non-standard combination has an actual number of connections (actual) that is much larger than the typical number of connections (typical), or the combination has not appeared for a long time, an alert is triggered. The Interflow includes the source host (srcip_host), destination IP address (dstip), destination port (dstport), application ID (appid), and application name (appid_name).

...

Stellar Cyber reports both internal and external versions of some alerts, with different analysis and recommended actions for each. Similarly, IDS signatures report the direction of data flow as inbound or outbound. Use the following as a guide for these concepts:

  • Addresses with a srcip_type or dstip_type of private are identified as internal. All other values are identified as external (when applicable; not all alerts have unique analytics for internal/external).
  • Communications between hosts where srcip_type and dstip_type are both private are considered internal communications.
  • When an anomaly is observed on an internal communication, the attack is considered to be internal.
  • Stellar Cyber always sets the srcip in the Interflow record as the initiating IP address of an event. Note that IDS signatures, which are reported with relevant alerts, instead list addresses based on the direction of data flow, not the initiating address. So an INBOUND data flow may show the dstip as the source address and the srcip as the destination address, even though the srcip was the initiator of the request. Use INBOUND and OUTBOUND information in the signature to understand the direction of data flow, together with Stellar Cyber’s Interflow record of srcip and dstip to understand which address initiated the threat event.

Unsupervised+Analytics

Y

External Other Malware

Malware with uncategorized malicious activity was observed. Check with the user.

XDR Kill Chain

  • Kill Chain Stage: Persistent Foothold

  • Tactic: [External] XDR Malware (XTA0006)

  • Technique: XDR Miscellaneous Malware (XT6001)

  • Tags: [External; Malware]

Event Name

The xdr_event.name for this alert type in the Interflow data is external_malware_activity.

Severity

50

Key Fields and Relevant Data Points

  • ids.signature — IDS signature  
  • maltrace-cloud.data.malicious_activity — malicious activity  
  • actual — number of records for one IDS signature or malicious activity in the period
  • lateral — boolean, indicating whether this activity is lateral (from private to private)
  • srcip_host — source host name
  • srcip_geo.countryName — source country
  • dstip_host — destination host name
  • dstip_geo.countryName — destination country
  • file_name — name of the file that carries the malware
  • event_source — source of the event, either ids or sandbox

Use Case with Data Points

If ML-IDS or sandbox indicates malware that cannot be categorized as ransomware, spyware, trojan, PUA, or adware, an alert is triggered. A sample Interflow includes malicious activity for sandbox (maltrace-cloud.data.malicious_activity), IDS signature for ML-IDS (ids.signature), event source (event_source), source host (srcip_host), source country (srcip_geo.countryName), destination host (dstip_host), destination country (dstip_geo.countryName), and the name of the file that carries the malware (file_name) from the sandbox.

...

Stellar Cyber reports both internal and external versions of some alerts, with different analysis and recommended actions for each. Similarly, IDS signatures report the direction of data flow as inbound or outbound. Use the following as a guide for these concepts:

  • Addresses with a srcip_type or dstip_type of private are identified as internal. All other values are identified as external (when applicable; not all alerts have unique analytics for internal/external).
  • Communications between hosts where srcip_type and dstip_type are both private are considered internal communications.
  • When an anomaly is observed on an internal communication, the attack is considered to be internal.
  • Stellar Cyber always sets the srcip in the Interflow record as the initiating IP address of an event. Note that IDS signatures, which are reported with relevant alerts, instead list addresses based on the direction of data flow, not the initiating address. So an INBOUND data flow may show the dstip as the source address and the srcip as the destination address, even though the srcip was the initiator of the request. Use INBOUND and OUTBOUND information in the signature to understand the direction of data flow, together with Stellar Cyber’s Interflow record of srcip and dstip to understand which address initiated the threat event.

Analytics

N

External Password Spraying

.An anomalously large number of failed logins with unknown user names was observed on external Windows authentication services. Check the activity after successful logins, and consider blocking the source IP addresses.

XDR Kill Chain

  • Kill Chain Stage: Initial Attempts

  • Tactic: Credential Access (TA0006 )

  • Technique: Brute Force (T1110 )

  • Sub-technique: Password Spraying (T1110.003 )

  • Tags: [External]

Event Name

The xdr_event.name for this alert type in the Interflow data is external_password_spray.

Severity

50

Key Fields and Relevant Data Points

  • srcip — source IP address generating a failed login 

    or

  • event_data.Workstation — workstation generating a failed login 

    The key field for this alert type can be either srcip or event_data.Workstation, depending on the data feed.

  • srcip_host — source host name
  • event_id — Windows event ID corresponding to the login failures
  • login_type — type of login protocol; the available values vary by event_id
  • actual — actual number of failed logins with unknown user names in a 5-minute period
  • typical — typical number of failed logins with unknown user names in a 5-minute period
  • password_spray_user_summary — list of up to 100 unknown user names associated with the failed logins (the first three are shown in the alert description)

Use Case with Data Points

If a potential password spraying attack is observed, an alert is triggered. The Interflow includes a source (srcip or event_data.Workstation), timestamp, the type of login (login_type), the number of failed logins (actual), the usual number of failed logins (typical), and a sampling of the user names used in the attack (password_spray_user_summary).

...

Stellar Cyber reports both internal and external versions of some alerts, with different analysis and recommended actions for each. Similarly, IDS signatures report the direction of data flow as inbound or outbound. Use the following as a guide for these concepts:

  • Addresses with a srcip_type or dstip_type of private are identified as internal. All other values are identified as external (when applicable; not all alerts have unique analytics for internal/external).
  • Communications between hosts where srcip_type and dstip_type are both private are considered internal communications.
  • When an anomaly is observed on an internal communication, the attack is considered to be internal.
  • Stellar Cyber always sets the srcip in the Interflow record as the initiating IP address of an event. Note that IDS signatures, which are reported with relevant alerts, instead list addresses based on the direction of data flow, not the initiating address. So an INBOUND data flow may show the dstip as the source address and the srcip as the destination address, even though the srcip was the initiator of the request. Use INBOUND and OUTBOUND information in the signature to understand the direction of data flow, together with Stellar Cyber’s Interflow record of srcip and dstip to understand which address initiated the threat event.

Unsupervised

Y

External PII Leaked

Personally identifiable information (social security numbers or credit cards) has been observed in the clear. Check the source to see if it is compromised. If so, consider blocking it.

XDR Kill Chain

  • Kill Chain Stage: Exfiltration & Impact

  • Tactic: [External] Exfiltration (TA0010 )

  • Technique: Automated Exfiltration (T1020 )

  • Tags: [External; Network Traffic Analysis]

Event Name

The xdr_event.name for this alert type in the Interflow data is external_pii_leak.

Severity

90

Key Fields and Relevant Data Points

  • srcip — source IP address of the PII leak 
  • dstip — destination IP address of the PII leak 
  • ids.signature — IDS signature 
  • srcip_host — host name of corresponding source IP address
  • dstip_host — host name of corresponding destination IP address

Use Case with Data Points

If a personally identifiable information leak is detected by IDS, an alert is triggered. A sample Interflow includes the IDS signature (ids.signature), source IP address (srcip), destination IP address (dstip), source host (srcip_host), and destination host (dstip_host).

...

Stellar Cyber reports both internal and external versions of some alerts, with different analysis and recommended actions for each. Similarly, IDS signatures report the direction of data flow as inbound or outbound. Use the following as a guide for these concepts:

  • Addresses with a srcip_type or dstip_type of private are identified as internal. All other values are identified as external (when applicable; not all alerts have unique analytics for internal/external).
  • Communications between hosts where srcip_type and dstip_type are both private are considered internal communications.
  • When an anomaly is observed on an internal communication, the attack is considered to be internal.
  • Stellar Cyber always sets the srcip in the Interflow record as the initiating IP address of an event. Note that IDS signatures, which are reported with relevant alerts, instead list addresses based on the direction of data flow, not the initiating address. So an INBOUND data flow may show the dstip as the source address and the srcip as the destination address, even though the srcip was the initiator of the request. Use INBOUND and OUTBOUND information in the signature to understand the direction of data flow, together with Stellar Cyber’s Interflow record of srcip and dstip to understand which address initiated the threat event.

Analytics

N

External Plain Text Passwords Detected

A plain text password was detected in unencrypted traffic. Check with the user.

XDR Kill Chain

  • Kill Chain Stage: Initial Attempts

  • Tactic: [External] XDR NBA (XTA0002)

  • Technique: XDR Clear Password (XT2006)

  • Tags: [External; Network Traffic Analysis]

Event Name

The xdr_event.name for this alert type in the Interflow data is external_clear_password.

Severity

10

Key Fields and Relevant Data Points

  • srcip — source IP address  
  • dstip — destination IP address 
  • actual — actual number of connections with a plain text password in the period
  • srcip_host — host name of corresponding source IP address
  • dstip_host — host name of corresponding destination IP address
  • appid_name — application name

Use Case with Data Points

If there are plain text passwords in unencrypted traffic records with a public source IP address (srcip) or destination IP address (dstip), an alert is triggered. A sample Interflow includes the source IP address (srcip), destination IP address (dstip), source host (srcip_host), destination host (dstip_host), and application (appid_name).

...

Stellar Cyber reports both internal and external versions of some alerts, with different analysis and recommended actions for each. Similarly, IDS signatures report the direction of data flow as inbound or outbound. Use the following as a guide for these concepts:

  • Addresses with a srcip_type or dstip_type of private are identified as internal. All other values are identified as external (when applicable; not all alerts have unique analytics for internal/external).
  • Communications between hosts where srcip_type and dstip_type are both private are considered internal communications.
  • When an anomaly is observed on an internal communication, the attack is considered to be internal.
  • Stellar Cyber always sets the srcip in the Interflow record as the initiating IP address of an event. Note that IDS signatures, which are reported with relevant alerts, instead list addresses based on the direction of data flow, not the initiating address. So an INBOUND data flow may show the dstip as the source address and the srcip as the destination address, even though the srcip was the initiator of the request. Use INBOUND and OUTBOUND information in the signature to understand the direction of data flow, together with Stellar Cyber’s Interflow record of srcip and dstip to understand which address initiated the threat event.

Analytics

N

External Protocol Account Login Failure Anomaly

An anomalously large number of login failures over SMB or FTP was observed. Check with the user.

XDR Kill Chain

  • Kill Chain Stage: Initial Attempts

  • Tactic: [External] Credential Access (TA0006 )

  • Technique: Brute Force (T1110 )

  • Tags: [External; Network Traffic Analysis]

Event Name

The xdr_event.name for this alert type in the Interflow data is external_protocol_account_login_failure.

Severity

35

Key Fields and Relevant Data Points

Use Case with Data Points

  • metadata.request.username — user name in the HTTP connection request  
  • event_summary.total_failed — number of failed logins in the period
  • event_summary.total_successful — number of successful logins in the period
  • event_summary.total_fail_ratio — percent of failed logins in the period, which is: event_summary.total_failed / (event_summary.total_failed + event_summary.total_successful)
  • weighted_anomaly_score — net score based on weighted rating of successful versus failed attempts (scanning, login, or other). Scores greater than upper threshold are potentially malicious and less than lower threshold are benign.
  • appid_name — application name
  • login_type — type of login
  • srcip_host — host name of corresponding source IP address
  • srcip_reputation — source reputation

For every user name (metadata.request.username) in the HTTP connections names (that do not begin with "Mozilla" or "Aella"), the number of failed and successful logins are calculated periodically. If the number of failed logins is much greater than successful logins, an alert is triggered. The Interflow includes the application name (appid_name), login type (login_type), source host (srcip_host), and source reputation (srcip_reputation).

...

Stellar Cyber reports both internal and external versions of some alerts, with different analysis and recommended actions for each. Similarly, IDS signatures report the direction of data flow as inbound or outbound. Use the following as a guide for these concepts:

  • Addresses with a srcip_type or dstip_type of private are identified as internal. All other values are identified as external (when applicable; not all alerts have unique analytics for internal/external).
  • Communications between hosts where srcip_type and dstip_type are both private are considered internal communications.
  • When an anomaly is observed on an internal communication, the attack is considered to be internal.
  • Stellar Cyber always sets the srcip in the Interflow record as the initiating IP address of an event. Note that IDS signatures, which are reported with relevant alerts, instead list addresses based on the direction of data flow, not the initiating address. So an INBOUND data flow may show the dstip as the source address and the srcip as the destination address, even though the srcip was the initiator of the request. Use INBOUND and OUTBOUND information in the signature to understand the direction of data flow, together with Stellar Cyber’s Interflow record of srcip and dstip to understand which address initiated the threat event.

Unsupervised

N

External PUA

Unwanted applications or malware that bombards the user with advertisements has been observed. Check with the user.

XDR Kill Chain

  • Kill Chain Stage: Persistent Foothold

  • Tactic: [External] XDR Malware (XTA0006)

  • Technique: XDR PUA (XT6002)

  • Tags: [External; Malware]

Event Name

The xdr_event.name for this alert type in the Interflow data is external_pua.

Severity

40

Key Fields and Relevant Data Points

  • ids.signature — IDS signature  
  • maltrace-cloud.data.malicious_activity — malicious activity  
  • actual — number of records for one IDS signature or malicious activity in the period
  • lateral — boolean, indicating whether this activity is lateral (from private to private)
  • srcip_host — source host name
  • srcip_geo.countryName — source country
  • dstip_host — destination host name
  • dstip_geo.countryName — destination country
  • file_name — name of the file that carries the PUA
  • event_source — source of the event, either ids or sandbox

Use Case with Data Points

If ML-IDS or sandbox indicates potentially unwanted applications (PUA), an alert is triggered. A sample Interflow includes malicious activity for sandbox (maltrace-cloud.data.malicious_activity) or IDS signature for ML-IDS (ids.signature), along with event source (event_source), source host (srcip_host), source country (srcip_geo.countryName), destination host (dstip_host), destination country (dstip_geo.countryName), and the name of the file that carries the PUA (file_name) from the sandbox.

...

Stellar Cyber reports both internal and external versions of some alerts, with different analysis and recommended actions for each. Similarly, IDS signatures report the direction of data flow as inbound or outbound. Use the following as a guide for these concepts:

  • Addresses with a srcip_type or dstip_type of private are identified as internal. All other values are identified as external (when applicable; not all alerts have unique analytics for internal/external).
  • Communications between hosts where srcip_type and dstip_type are both private are considered internal communications.
  • When an anomaly is observed on an internal communication, the attack is considered to be internal.
  • Stellar Cyber always sets the srcip in the Interflow record as the initiating IP address of an event. Note that IDS signatures, which are reported with relevant alerts, instead list addresses based on the direction of data flow, not the initiating address. So an INBOUND data flow may show the dstip as the source address and the srcip as the destination address, even though the srcip was the initiator of the request. Use INBOUND and OUTBOUND information in the signature to understand the direction of data flow, together with Stellar Cyber’s Interflow record of srcip and dstip to understand which address initiated the threat event.

Analytics

N

External Ransomware

Malware that prevents you from accessing your system or files and demands ransom payment in order to regain access was observed. Check with the user.

XDR Kill Chain

  • Kill Chain Stage: Exfiltration & Impact

  • Tactic: [External] Impact (TA0040 )

  • Technique: Data Encrypted for Impact (T1486 )

  • Tags: [External; Malware; Ransomware]

Event Name

The xdr_event.name for this alert type in the Interflow data is external_ransomware.

Severity

80

Key Fields and Relevant Data Points

  • ids.signature — IDS signature  
  • maltrace-cloud.data.malicious_activity — malicious activity  
  • actual — number of records for one IDS signature or malicious activity in the period
  • lateral — boolean, indicating whether this activity is lateral (from private to private)
  • srcip_host — source host name
  • srcip_geo.countryName — source country
  • dstip_host — destination host name
  • dstip_geo.countryName — destination country
  • file_name — name of the file that carries the ransomware
  • event_source — source of the event, either ids or sandbox

Use Case with Data Points

If ML-IDS or sandbox indicates ransomware, an alert is triggered. A sample Interflow includes malicious activity for sandbox (maltrace-cloud.data.malicious_activity), IDS signature for ML-IDS (ids.signature), event source (event_source), source host (srcip_host), source country (srcip_geo.countryName), destination host (dstip_host), destination country (dstip_geo.countryName), and the name of the file that carries the ransomware (file_name) from the sandbox.

...

Stellar Cyber reports both internal and external versions of some alerts, with different analysis and recommended actions for each. Similarly, IDS signatures report the direction of data flow as inbound or outbound. Use the following as a guide for these concepts:

  • Addresses with a srcip_type or dstip_type of private are identified as internal. All other values are identified as external (when applicable; not all alerts have unique analytics for internal/external).
  • Communications between hosts where srcip_type and dstip_type are both private are considered internal communications.
  • When an anomaly is observed on an internal communication, the attack is considered to be internal.
  • Stellar Cyber always sets the srcip in the Interflow record as the initiating IP address of an event. Note that IDS signatures, which are reported with relevant alerts, instead list addresses based on the direction of data flow, not the initiating address. So an INBOUND data flow may show the dstip as the source address and the srcip as the destination address, even though the srcip was the initiator of the request. Use INBOUND and OUTBOUND information in the signature to understand the direction of data flow, together with Stellar Cyber’s Interflow record of srcip and dstip to understand which address initiated the threat event.

Analytics

N

External RDP BlueKeep

Detects the use of a scanner by zerosum0x0 that discovers targets vulnerable to BlueKeep (CVE-2019-0708) has been observed. Check the IP address and block if necessary.

XDR Kill Chain

  • Kill Chain Stage: Propagation

  • Tactic: [External] Privilege Escalation (TA0004 )

  • Technique: Exploitation for Privilege Escalation (T1068 )

  • Tags: [External; RDP]

Event Name

The xdr_event.name for this alert type in the Interflow data is external_rdp_bluekeep.

Severity

80

Key Fields and Relevant Data Points

  • ids.signature — IDS signature  
  • srcip_host — source host name 
  • dstip_host — destination host name 

Use Case with Data Points

If the scanner by zerosum0x0 is used, an alert is triggered. A sample Interflow includes the IDS signature (ids.signature), source host (srcip_host), and destination host (dstip_host).

...

Stellar Cyber reports both internal and external versions of some alerts, with different analysis and recommended actions for each. Similarly, IDS signatures report the direction of data flow as inbound or outbound. Use the following as a guide for these concepts:

  • Addresses with a srcip_type or dstip_type of private are identified as internal. All other values are identified as external (when applicable; not all alerts have unique analytics for internal/external).
  • Communications between hosts where srcip_type and dstip_type are both private are considered internal communications.
  • When an anomaly is observed on an internal communication, the attack is considered to be internal.
  • Stellar Cyber always sets the srcip in the Interflow record as the initiating IP address of an event. Note that IDS signatures, which are reported with relevant alerts, instead list addresses based on the direction of data flow, not the initiating address. So an INBOUND data flow may show the dstip as the source address and the srcip as the destination address, even though the srcip was the initiator of the request. Use INBOUND and OUTBOUND information in the signature to understand the direction of data flow, together with Stellar Cyber’s Interflow record of srcip and dstip to understand which address initiated the threat event.

Analytics

N

External RDP Brute Force Attack

An anomalously large number of RDP connections to an RDP server was observed. Check the source IP addresses to determine if they are unknown or malicious, and monitor any successful RDP logins.

XDR Kill Chain

  • Kill Chain Stage: Initial Attempts

  • Tactic: [External] Credential Access (TA0006 )

  • Technique: Brute Force (T1110 )

  • Tags: [External; Network Traffic Analysis]

Event Name

The xdr_event.name for this alert type in the Interflow data is external_rdp_brute_force.

Severity

30

Key Fields and Relevant Data Points

  • dstip — IP address of the destination RDP server  
  • dstip_host — destination host name
  • actual — actual number of RDP connections to the destination IP address in the observed time bucket
  • typical — typical number of RDP connections to the destination IP address in most time buckets
  • srcip — source IP address
  • srcip_host — source host name

Use Case with Data Points

RDP connection activity is monitored and the number of connections are calculated periodically. If the number of connections to an RDP server (actual) is much greater than normal (typical), an alert is triggered. A sample Interflow includes the destination IP address (dstip) and source IP address (srcip).

...

Stellar Cyber reports both internal and external versions of some alerts, with different analysis and recommended actions for each. Similarly, IDS signatures report the direction of data flow as inbound or outbound. Use the following as a guide for these concepts:

  • Addresses with a srcip_type or dstip_type of private are identified as internal. All other values are identified as external (when applicable; not all alerts have unique analytics for internal/external).
  • Communications between hosts where srcip_type and dstip_type are both private are considered internal communications.
  • When an anomaly is observed on an internal communication, the attack is considered to be internal.
  • Stellar Cyber always sets the srcip in the Interflow record as the initiating IP address of an event. Note that IDS signatures, which are reported with relevant alerts, instead list addresses based on the direction of data flow, not the initiating address. So an INBOUND data flow may show the dstip as the source address and the srcip as the destination address, even though the srcip was the initiator of the request. Use INBOUND and OUTBOUND information in the signature to understand the direction of data flow, together with Stellar Cyber’s Interflow record of srcip and dstip to understand which address initiated the threat event.

Unsupervised

Y

External RDP Suspicious Outbound

Non-standard tools connecting to TCP port 3389 were observed. This could indicate lateral movement attempting to establish an RDP connection. Check the IP address and block if necessary.

XDR Kill Chain

  • Kill Chain Stage: Initial Attempts

  • Tactic: [External] XDR NBA (XTA0002)

  • Technique: XDR App Anomaly (XT2003)

  • Tags: [External; RDP]

Event Name

The xdr_event.name for this alert type in the Interflow data is external_rdp_suspicious_outbound.

Severity

60

Key Fields and Relevant Data Points

  • srcip — source IP address of the host that connects to TCP port 3389 with a non-standard tool 
  • srcip_host — source host name
  • process_name — process name

Use Case with Data Points

Connections to TCP port 3389 are monitored, and if non-standard tools connect, an alert is triggered. A sample Interflow includes the source IP address (srcip) and the process name (process_name). The following are the standard tools:

  • mstsc.exe
  • RTSApp.exe
  • RTS2App.exe
  • RDCMan.exe
  • ws_TunnelService.exe
  • RSSensor.exe
  • RemoteDesktopManagerFree.exe
  • RemoteDesktopManager.exe
  • RemoteDesktopManager64.exe
  • mRemoteNG.exe
  • mRemote.exe
  • Terminals.exe
  • spiceworks-finder.exe
  • FSDiscovery.exe
  • FSAssessment.exe
  • MobaRTE.exe
  • chrome.exe
  • thor.exe
  • thor64.exe

...

Stellar Cyber reports both internal and external versions of some alerts, with different analysis and recommended actions for each. Similarly, IDS signatures report the direction of data flow as inbound or outbound. Use the following as a guide for these concepts:

  • Addresses with a srcip_type or dstip_type of private are identified as internal. All other values are identified as external (when applicable; not all alerts have unique analytics for internal/external).
  • Communications between hosts where srcip_type and dstip_type are both private are considered internal communications.
  • When an anomaly is observed on an internal communication, the attack is considered to be internal.
  • Stellar Cyber always sets the srcip in the Interflow record as the initiating IP address of an event. Note that IDS signatures, which are reported with relevant alerts, instead list addresses based on the direction of data flow, not the initiating address. So an INBOUND data flow may show the dstip as the source address and the srcip as the destination address, even though the srcip was the initiator of the request. Use INBOUND and OUTBOUND information in the signature to understand the direction of data flow, together with Stellar Cyber’s Interflow record of srcip and dstip to understand which address initiated the threat event.

Analytics

N

External Scanner Behavior Anomaly

An anomalously large amount of scanning behavior or a rarely seen scan behavior was found. Cross-check with the IP/Port Scan Anomaly alert.

XDR Kill Chain

  • Kill Chain Stage: Initial Attempts

  • Tactic: [External] Reconnaissance (TA0043 )

  • Technique: Active Scanning (T1595 )

  • Tags: [External; Network Traffic Analysis]

Event Name

The xdr_event.name for this alert type in the Interflow data is external_scan_anomalies.

Severity

10

Key Fields and Relevant Data Points

  • ids.signature — signature of the exploit  
  • actual — actual number of times this signature was found in the period, with critical IDS signatures counted as 2, high counted as 1, low counted as 0.5, and others counted as 1
  • typical — typical number of times this signature is seen in the period, with critical IDS signatures counted as 2, high counted as 1, low counted as 0.5, and others counted as 1
  • srcip_host — host name of corresponding source IP address
  • dstip_host — host name of corresponding destination IP address
  • appid_name — application name

Use Case with Data Points

The number of occurrences of each scanner, based on IDS signature (ids.signature), is calculated periodically. If one scanner occurs (actual) much more often than its history (typical), an alert is triggered. The Interflow includes information such as the traffic application type (appid_name), source (srcip_host), and destination (dstip_host).

...

Stellar Cyber reports both internal and external versions of some alerts, with different analysis and recommended actions for each. Similarly, IDS signatures report the direction of data flow as inbound or outbound. Use the following as a guide for these concepts:

  • Addresses with a srcip_type or dstip_type of private are identified as internal. All other values are identified as external (when applicable; not all alerts have unique analytics for internal/external).
  • Communications between hosts where srcip_type and dstip_type are both private are considered internal communications.
  • When an anomaly is observed on an internal communication, the attack is considered to be internal.
  • Stellar Cyber always sets the srcip in the Interflow record as the initiating IP address of an event. Note that IDS signatures, which are reported with relevant alerts, instead list addresses based on the direction of data flow, not the initiating address. So an INBOUND data flow may show the dstip as the source address and the srcip as the destination address, even though the srcip was the initiator of the request. Use INBOUND and OUTBOUND information in the signature to understand the direction of data flow, together with Stellar Cyber’s Interflow record of srcip and dstip to understand which address initiated the threat event.

Unsupervised

Y

External SMB Read Anomaly

An IP address sent an anomalously large number of read requests to SMB protocol based service(s). Investigate the files that the IP address tried to read. If suspicious, block the source IP address.

XDR Kill Chain

  • Kill Chain Stage: Initial Attempts

  • Tactic: [External] Initial Access (TA0001 )

  • Technique: Exploit Public-Facing Application (T1190 )

  • Tags: [External; Network Traffic Analysis]

Event Name

The xdr_event.name for this alert type in the Interflow data is external_smb_read_anomaly.

Severity

15

Key Fields and Relevant Data Points

  • srcip — source IP address  
  • srcip_host — source host name
  • actual — actual number of SMB reads from the source IP address in the period
  • typical — typical number of SMB reads from other source IP addresses in the period
  • dstip_host — destination host name
  • smb_username — SMB user name

Use Case with Data Points

The number of SMB read requests for every source IP address (srcip) is calculated periodically. If a source IP address’s number of SMB reads (actual) is much larger than the typical number (typical) and that of other IP addresses in any period, an alert is triggered. The Interflow includes the SMB user (smb_username) and destination host (dstip_host).

...

Stellar Cyber reports both internal and external versions of some alerts, with different analysis and recommended actions for each. Similarly, IDS signatures report the direction of data flow as inbound or outbound. Use the following as a guide for these concepts:

  • Addresses with a srcip_type or dstip_type of private are identified as internal. All other values are identified as external (when applicable; not all alerts have unique analytics for internal/external).
  • Communications between hosts where srcip_type and dstip_type are both private are considered internal communications.
  • When an anomaly is observed on an internal communication, the attack is considered to be internal.
  • Stellar Cyber always sets the srcip in the Interflow record as the initiating IP address of an event. Note that IDS signatures, which are reported with relevant alerts, instead list addresses based on the direction of data flow, not the initiating address. So an INBOUND data flow may show the dstip as the source address and the srcip as the destination address, even though the srcip was the initiator of the request. Use INBOUND and OUTBOUND information in the signature to understand the direction of data flow, together with Stellar Cyber’s Interflow record of srcip and dstip to understand which address initiated the threat event.

Unsupervised

Y

External SMB Username Enumeration

At least 5 different users SMB login attempts and 1 denied attempt or at least 10 different users SMB login attempts, were observed from the same source. Check the source IP address. If malicious, consider blocking it.

XDR Kill Chain

  • Kill Chain Stage: Initial Attempts

  • Tactic: [External] Credential Access (TA0006 )

  • Technique: Brute Force (T1110 )

  • Tags: [External; Network Traffic Analysis]

Event Name

The xdr_event.name for this alert type in the Interflow data is external_smb_user_scan.

Severity

40

Key Fields and Relevant Data Points

  • srcip — source IP address  
  • srcip_host — host name of corresponding source IP address
  • dstip_host — host name of corresponding destination IP address
  • actual — actual unique SMB user count
  • typical — SMB user count threshold
  • smb_username_set — all SMB login user names

Use Case with Data Points

If one source IP address (srcip) has several SMB login attempts with (1) at least 5 unique user names and at least 1 denied attempt or (2) at least 10 unique user names, an alert is triggered. A sample Interflow includes the source IP address (srcip), source host (srcip_host), destination host (dstip_host), and all the user names (smb_username_set).

...

Stellar Cyber reports both internal and external versions of some alerts, with different analysis and recommended actions for each. Similarly, IDS signatures report the direction of data flow as inbound or outbound. Use the following as a guide for these concepts:

  • Addresses with a srcip_type or dstip_type of private are identified as internal. All other values are identified as external (when applicable; not all alerts have unique analytics for internal/external).
  • Communications between hosts where srcip_type and dstip_type are both private are considered internal communications.
  • When an anomaly is observed on an internal communication, the attack is considered to be internal.
  • Stellar Cyber always sets the srcip in the Interflow record as the initiating IP address of an event. Note that IDS signatures, which are reported with relevant alerts, instead list addresses based on the direction of data flow, not the initiating address. So an INBOUND data flow may show the dstip as the source address and the srcip as the destination address, even though the srcip was the initiator of the request. Use INBOUND and OUTBOUND information in the signature to understand the direction of data flow, together with Stellar Cyber’s Interflow record of srcip and dstip to understand which address initiated the threat event.

Analytics

N

External SMB Write Anomaly

An IP address sent an anomalously large number of SMB write requests. Investigate the files that the IP address tried to write. If suspicious, block the source IP address.

XDR Kill Chain

  • Kill Chain Stage: Exfiltration & Impact

  • Tactic: [External] Impact (TA0040 )

  • Technique: Data Manipulation (T1565 )

  • Tags: [External; Network Traffic Analysis]

Event Name

The xdr_event.name for this alert type in the Interflow data is external_smb_anomaly.

Severity

30

Key Fields and Relevant Data Points

  • srcip_host — source host name 
  • actual — actual number of SMB writes in the period
  • typical — typical number of SMB writes in the period
  • dstip_host — destination host name
  • smb_username — SMB user name

Use Case with Data Points

The number of SMB write requests for every source IP address (srcip_host) is calculated periodically. If a source IP address’s number of SMB writes (actual) is much larger than the typical number (typical) and that of other IP addresses in any period, an alert is triggered. The Interflow includes the SMB user (smb_username) and destination host (dstip_host).

...

Stellar Cyber reports both internal and external versions of some alerts, with different analysis and recommended actions for each. Similarly, IDS signatures report the direction of data flow as inbound or outbound. Use the following as a guide for these concepts:

  • Addresses with a srcip_type or dstip_type of private are identified as internal. All other values are identified as external (when applicable; not all alerts have unique analytics for internal/external).
  • Communications between hosts where srcip_type and dstip_type are both private are considered internal communications.
  • When an anomaly is observed on an internal communication, the attack is considered to be internal.
  • Stellar Cyber always sets the srcip in the Interflow record as the initiating IP address of an event. Note that IDS signatures, which are reported with relevant alerts, instead list addresses based on the direction of data flow, not the initiating address. So an INBOUND data flow may show the dstip as the source address and the srcip as the destination address, even though the srcip was the initiator of the request. Use INBOUND and OUTBOUND information in the signature to understand the direction of data flow, together with Stellar Cyber’s Interflow record of srcip and dstip to understand which address initiated the threat event.

Analytics

N

External Spyware

Malware that collects and shares information about a device without consent was observed. Check with the user.

XDR Kill Chain

  • Kill Chain Stage: Persistent Foothold

  • Tactic: [External] XDR Malware (XTA0006)

  • Technique: XDR Spyware (XT6003)

  • Tags: [External; Malware]

Event Name

The xdr_event.name for this alert type in the Interflow data is external_spyware_activity.

Severity

40

Key Fields and Relevant Data Points

  • ids.signature — IDS signature  
  • maltrace-cloud.data.malicious_activity — malicious activity  
  • actual — number of records for one IDS signature or malicious activity in the period
  • lateral — boolean, indicating whether this activity is lateral (from private to private)
  • srcip_host — source host name
  • srcip_geo.countryName — source country
  • dstip_host — destination host name
  • dstip_geo.countryName — destination country
  • file_name — name of the file that carries the spyware
  • event_source — source of the event, either ids or sandbox

Use Case with Data Points

If ML-IDS or sandbox indicates spyware activity, an alert is triggered. A sample Interflow includes malicious activity for sandbox (maltrace-cloud.data.malicious_activity), IDS signature for ML-IDS (ids.signature), event source (event_source), source host (srcip_host), source country (srcip_geo.countryName), destination host (dstip_host), destination country (dstip_geo.countryName), and the name of the file that carries the spyware (file_name) from the sandbox.

...

Stellar Cyber reports both internal and external versions of some alerts, with different analysis and recommended actions for each. Similarly, IDS signatures report the direction of data flow as inbound or outbound. Use the following as a guide for these concepts:

  • Addresses with a srcip_type or dstip_type of private are identified as internal. All other values are identified as external (when applicable; not all alerts have unique analytics for internal/external).
  • Communications between hosts where srcip_type and dstip_type are both private are considered internal communications.
  • When an anomaly is observed on an internal communication, the attack is considered to be internal.
  • Stellar Cyber always sets the srcip in the Interflow record as the initiating IP address of an event. Note that IDS signatures, which are reported with relevant alerts, instead list addresses based on the direction of data flow, not the initiating address. So an INBOUND data flow may show the dstip as the source address and the srcip as the destination address, even though the srcip was the initiator of the request. Use INBOUND and OUTBOUND information in the signature to understand the direction of data flow, together with Stellar Cyber’s Interflow record of srcip and dstip to understand which address initiated the threat event.

Analytics

N

External SQL Anomaly

An IP address sent an anomalously large number of queries to one or more SQL servers. Investigate the queries. If suspicious, block the source IP address.

XDR Kill Chain

  • Kill Chain Stage: Initial Attempts

  • Tactic: [External] Initial Access (TA0001 )

  • Technique: Exploit Public-Facing Application (T1190 )

  • Tags: [External; Network Traffic Analysis]

Event Name

The xdr_event.name for this alert type in the Interflow data is external_mysql_anomaly.

Severity

15

Key Fields and Relevant Data Points

  • srcip — source IP address 
  • srcip_host — source host name
  • srcip_geo.countryName — name of the source country
  • actual — actual number of SQL queries in the period
  • typical — typical number of SQL queries from the source IP address
  • dstip_host — host name of corresponding destination IP address

Use Case with Data Points

The number of SQL queries for every source IP address (srcip_host) is calculated periodically. If a source IP’s SQL query count (actual) is much larger than the typical count (typical) and that of other IP addresses in any period, an alert is triggered. The source IP’s country is (srcip_geo.countryName). The Interflow includes the destination host (dstip_host) the source IP visits.

...

Stellar Cyber reports both internal and external versions of some alerts, with different analysis and recommended actions for each. Similarly, IDS signatures report the direction of data flow as inbound or outbound. Use the following as a guide for these concepts:

  • Addresses with a srcip_type or dstip_type of private are identified as internal. All other values are identified as external (when applicable; not all alerts have unique analytics for internal/external).
  • Communications between hosts where srcip_type and dstip_type are both private are considered internal communications.
  • When an anomaly is observed on an internal communication, the attack is considered to be internal.
  • Stellar Cyber always sets the srcip in the Interflow record as the initiating IP address of an event. Note that IDS signatures, which are reported with relevant alerts, instead list addresses based on the direction of data flow, not the initiating address. So an INBOUND data flow may show the dstip as the source address and the srcip as the destination address, even though the srcip was the initiator of the request. Use INBOUND and OUTBOUND information in the signature to understand the direction of data flow, together with Stellar Cyber’s Interflow record of srcip and dstip to understand which address initiated the threat event.

Unsupervised

Y

External SQL Dumpfile Execution

The SQL dumpfile command was observed. This command is commonly used to dump database content or query output to a file on disk. Check with the user.

XDR Kill Chain

  • Kill Chain Stage: Exploration

  • Tactic: [External] Collection (TA0009 )

  • Technique: Data Staged (T1074 )

  • Tags: [External; Network Traffic Analysis]

Event Name

The xdr_event.name for this alert type in the Interflow data is external_sql_db_dump.

Severity

75

Key Fields and Relevant Data Points

  • srcip — source IP address  
  • actual — number of SQL dumpfile queries
  • srcip_host — source host name
  • source_geo.countryName — source country
  • dstip_host — destination host name

Use Case with Data Points

If the SQL dumpfile command is seen on any source IP address (srcip), an alert is triggered. A sample Interflow includes the source IP address (srcip), source host (srcip_host), source country (srcip_geo.countryName), destination host (dstip_host), and number of SQL dumpfile queries in the period (actual).

...

Stellar Cyber reports both internal and external versions of some alerts, with different analysis and recommended actions for each. Similarly, IDS signatures report the direction of data flow as inbound or outbound. Use the following as a guide for these concepts:

  • Addresses with a srcip_type or dstip_type of private are identified as internal. All other values are identified as external (when applicable; not all alerts have unique analytics for internal/external).
  • Communications between hosts where srcip_type and dstip_type are both private are considered internal communications.
  • When an anomaly is observed on an internal communication, the attack is considered to be internal.
  • Stellar Cyber always sets the srcip in the Interflow record as the initiating IP address of an event. Note that IDS signatures, which are reported with relevant alerts, instead list addresses based on the direction of data flow, not the initiating address. So an INBOUND data flow may show the dstip as the source address and the srcip as the destination address, even though the srcip was the initiator of the request. Use INBOUND and OUTBOUND information in the signature to understand the direction of data flow, together with Stellar Cyber’s Interflow record of srcip and dstip to understand which address initiated the threat event.

Analytics

N

External SQL Shell Command

Shell commands were observed over a SQL connection, which is a common way hackers try to gain shell access over vulnerable SQL applications. Check with the user.

XDR Kill Chain

  • Kill Chain Stage: Persistent Foothold

  • Tactic: [External] Execution (TA0002 )

  • Technique: Command and Scripting Interpreter (T1059 )

  • Tags: [External; Network Traffic Analysis]

Event Name

The xdr_event.name for this alert type in the Interflow data is external_database_command.

Severity

40

Key Fields and Relevant Data Points

  • srcip — source IP address  
  • dstip — destination IP address  
  • srcip_host — source host name
  • srcip_reputation — source reputation
  • dstip_host — destination host name
  • dstip_reputation — destination reputation
  • metadata.request.query — SQL query command
  • actual — number of query records from one source to one destination in one period

Use Case with Data Points

For SQL query records, if special commands (such as select mylab_sys_exec) are found, an alert is triggered. A sample Interflow includes the source IP address (srcip), destination IP address (dstip), source host (srcip_host), source reputation (srcip_reputation), destination host (dstip_host), destination reputation (dstip_reputation), and SQL query records (metadata.request.query).

...

Stellar Cyber reports both internal and external versions of some alerts, with different analysis and recommended actions for each. Similarly, IDS signatures report the direction of data flow as inbound or outbound. Use the following as a guide for these concepts:

  • Addresses with a srcip_type or dstip_type of private are identified as internal. All other values are identified as external (when applicable; not all alerts have unique analytics for internal/external).
  • Communications between hosts where srcip_type and dstip_type are both private are considered internal communications.
  • When an anomaly is observed on an internal communication, the attack is considered to be internal.
  • Stellar Cyber always sets the srcip in the Interflow record as the initiating IP address of an event. Note that IDS signatures, which are reported with relevant alerts, instead list addresses based on the direction of data flow, not the initiating address. So an INBOUND data flow may show the dstip as the source address and the srcip as the destination address, even though the srcip was the initiator of the request. Use INBOUND and OUTBOUND information in the signature to understand the direction of data flow, together with Stellar Cyber’s Interflow record of srcip and dstip to understand which address initiated the threat event.

Analytics

N

External Suspected Malicious User Agent

An external HTTP connection was made by a user agent that has been identified as potentially malicious. Investigate the connection's destination.

This alert type has two subtypes:

XDR Kill Chain

  • Kill Chain Stage: Initial Attempts

  • Tactic: [External] XDR NBA (XTA0002)

  • Technique: XDR User Agent Anomaly (XT2012)

  • Tags: [External; Network Traffic Analysis]

Event Name

The xdr_event.name for this alert type in the Interflow data is external_suspected_malicious_user_agent.

Severity

30

Key Fields and Relevant Data Points

  • metadata.request.user_agent — user agent in the HTTP connection request  
  • stellar.confidence — model's confidence in the prediction
  • srcip_host — host name of corresponding source IP address
  • dstip_host — host name of corresponding destination IP address
  • appid_name — application name

Use Case with Data Points

If a seen user agent is identified as suspicious, an alert is triggered. The alert includes the suspicious user agent (metadata.request.user_agent), confidence (stellar.confidence), tenant (tenant_name), source IP (srcip), and destination IP (dstip) in the key fields. Additionally, the confidence level of the model is displayed in the alert description in a pop-up box.

Alert Subtype: Predicted Malicious Agent

The Predicted Malicious Agent alert subtype is the same as the External Suspected Malicious User Agent alert type above, with the following differences:

  • The stellar.anomaly_tag is predicted_external.

  • The xdr_event.subtype.name is external_suspected_malicious_user_agent.

  • It is triggered by a machine learning classifier.

Alert Subtype: Known Malicious Agent Match

The Known Malicious Agent Match alert subtype is the same as the External Suspected Malicious User Agent alert type above, with the following differences:

  • The stellar.anomaly_tag is known_external.

  • The xdr_event.subtype.name is external_suspected_malicious_user_agent_known_malicious.

  • It is triggered by known threats.

...

Stellar Cyber reports both internal and external versions of some alerts, with different analysis and recommended actions for each. Similarly, IDS signatures report the direction of data flow as inbound or outbound. Use the following as a guide for these concepts:

  • Addresses with a srcip_type or dstip_type of private are identified as internal. All other values are identified as external (when applicable; not all alerts have unique analytics for internal/external).
  • Communications between hosts where srcip_type and dstip_type are both private are considered internal communications.
  • When an anomaly is observed on an internal communication, the attack is considered to be internal.
  • Stellar Cyber always sets the srcip in the Interflow record as the initiating IP address of an event. Note that IDS signatures, which are reported with relevant alerts, instead list addresses based on the direction of data flow, not the initiating address. So an INBOUND data flow may show the dstip as the source address and the srcip as the destination address, even though the srcip was the initiator of the request. Use INBOUND and OUTBOUND information in the signature to understand the direction of data flow, together with Stellar Cyber’s Interflow record of srcip and dstip to understand which address initiated the threat event.

Supervised

N

External SYN Flood Attacker

An attacker sends a large amount of SYN requests to a target's system in an attempt to consume enough server resources to make the system unresponsive to legitimate traffic.

XDR Kill Chain

  • Kill Chain Stage: Exfiltration & Impact

  • Tactic: [External] Impact (TA0040 )

  • Technique: Endpoint Denial of Service (T1499 )

  • Tags: [External; Network Traffic Analysis]

Event Name

The xdr_event.name for this alert type in the Interflow data is external_syn_flood_attacker.

Severity

10

Key Fields and Relevant Data Points

  • srcip — source IP address of the SYN flood  
  • srcip_host — source host name
  • dstip — target IP address of the SYN flood
  • dstip_host — destination host name
  • dstport — port on target host that received the SYN flood
  • syn_flood_events — number of SYN packets during the period

Use Case with Data Points

If an external host (srcip) sends too many SYN packets (syn_flood_events) to internal target(s) (dstip) in a five-minute time window, an alert is triggered. The Interflow includes the IP address of the source host (srcip), the IP address of the target host (dstip), the port of the target host (dstport), and how many SYN packets were observed (actual).

...

Stellar Cyber reports both internal and external versions of some alerts, with different analysis and recommended actions for each. Similarly, IDS signatures report the direction of data flow as inbound or outbound. Use the following as a guide for these concepts:

  • Addresses with a srcip_type or dstip_type of private are identified as internal. All other values are identified as external (when applicable; not all alerts have unique analytics for internal/external).
  • Communications between hosts where srcip_type and dstip_type are both private are considered internal communications.
  • When an anomaly is observed on an internal communication, the attack is considered to be internal.
  • Stellar Cyber always sets the srcip in the Interflow record as the initiating IP address of an event. Note that IDS signatures, which are reported with relevant alerts, instead list addresses based on the direction of data flow, not the initiating address. So an INBOUND data flow may show the dstip as the source address and the srcip as the destination address, even though the srcip was the initiator of the request. Use INBOUND and OUTBOUND information in the signature to understand the direction of data flow, together with Stellar Cyber’s Interflow record of srcip and dstip to understand which address initiated the threat event.

Analytics

N

External SYN Flood Victim

A large amount of SYN requests were observed, which can indicate an attempt to consume server resources and make the target unresponsive. Check to see if the host is malicious or compromised. If so, consider blocking the source host.

XDR Kill Chain

  • Kill Chain Stage: Exfiltration & Impact

  • Tactic: [External] Impact (TA0040 )

  • Technique: Endpoint Denial of Service (T1499 )

  • Tags: [External; Network Traffic Analysis]

Event Name

The xdr_event.name for this alert type in the Interflow data is external_syn_flood.

Severity

10

Key Fields and Relevant Data Points

  • dstip — target IP address of the SYN flood  
  • srcip — source IP address of the SYN flood
  • srcip_host — source host name
  • dstip_host — destination host name
  • dstport — port on target host that received the SYN flood
  • syn_flood_events — number of SYN packets during the period

Use Case with Data Points

If an external host (srcip) sends too many SYN packets (syn_flood_events) to internal target(s) (dstip) in a five-minute time window, an alert is triggered. The Interflow includes the IP address of the source host (srcip), the IP address of the target host (dstip), the port of the target host (dstport), and how many SYN packets were observed (actual).

...

Stellar Cyber reports both internal and external versions of some alerts, with different analysis and recommended actions for each. Similarly, IDS signatures report the direction of data flow as inbound or outbound. Use the following as a guide for these concepts:

  • Addresses with a srcip_type or dstip_type of private are identified as internal. All other values are identified as external (when applicable; not all alerts have unique analytics for internal/external).
  • Communications between hosts where srcip_type and dstip_type are both private are considered internal communications.
  • When an anomaly is observed on an internal communication, the attack is considered to be internal.
  • Stellar Cyber always sets the srcip in the Interflow record as the initiating IP address of an event. Note that IDS signatures, which are reported with relevant alerts, instead list addresses based on the direction of data flow, not the initiating address. So an INBOUND data flow may show the dstip as the source address and the srcip as the destination address, even though the srcip was the initiator of the request. Use INBOUND and OUTBOUND information in the signature to understand the direction of data flow, together with Stellar Cyber’s Interflow record of srcip and dstip to understand which address initiated the threat event.

Analytics

N

External Trojan

Malware that disguises itself as legitimate software in order to gain access to a system or files has been observed. Check with the user.

XDR Kill Chain

  • Kill Chain Stage: Persistent Foothold

  • Tactic: [External] XDR Malware (XTA0006)

  • Technique: XDR Trojan (XT6004)

  • Tags: [External; Malware]

Event Name

The xdr_event.name for this alert type in the Interflow data is external_trojan_activity.

Severity

50

Key Fields and Relevant Data Points

  • ids.signature — IDS signature  
  • maltrace-cloud.data.malicious_activity — malicious activity  
  • actual — number of records for one IDS signature or malicious activity in the period
  • lateral — boolean, indicating whether this activity is lateral (from private to private)
  • srcip_host — source host name
  • srcip_geo.countryName — source country
  • dstip_host — destination host name
  • dstip_geo.countryName — destination country
  • file_name — name of the file that carries the trojan
  • event_source — source of the event, either ids or sandbox

Use Case with Data Points

If ML-IDS or sandbox indicates trojan activity, an alert is triggered. A sample Interflow includes malicious activity for sandbox (maltrace-cloud.data.malicious_activity), IDS signature for ML-IDS (ids.signature), event source (event_source), source host (srcip_host), source country (srcip_geo.countryName), destination host (dstip_host), destination country (dstip_geo.countryName), and the name of the file that carries the trojan (file_name) from the sandbox.

...

Stellar Cyber reports both internal and external versions of some alerts, with different analysis and recommended actions for each. Similarly, IDS signatures report the direction of data flow as inbound or outbound. Use the following as a guide for these concepts:

  • Addresses with a srcip_type or dstip_type of private are identified as internal. All other values are identified as external (when applicable; not all alerts have unique analytics for internal/external).
  • Communications between hosts where srcip_type and dstip_type are both private are considered internal communications.
  • When an anomaly is observed on an internal communication, the attack is considered to be internal.
  • Stellar Cyber always sets the srcip in the Interflow record as the initiating IP address of an event. Note that IDS signatures, which are reported with relevant alerts, instead list addresses based on the direction of data flow, not the initiating address. So an INBOUND data flow may show the dstip as the source address and the srcip as the destination address, even though the srcip was the initiator of the request. Use INBOUND and OUTBOUND information in the signature to understand the direction of data flow, together with Stellar Cyber’s Interflow record of srcip and dstip to understand which address initiated the threat event.

Analytics

N

External URL Reconnaissance Anomaly

An anomalous number of HTTP 4xx errors were observed. This can indicate an attacker scanning for pages to exploit. Check with the user.

XDR Kill Chain

  • Kill Chain Stage: Initial Attempts

  • Tactic: [External] Reconnaissance (TA0043 )

  • Technique: Active Scanning (T1595 )

  • Tags: [External; Network Traffic Analysis]

Event Name

The xdr_event.name for this alert type in the Interflow data is external_url_scan.

Severity

20

Key Fields and Relevant Data Points

  • srcip — source IP address  
  • event_summary.total_failed — number of unique URLs with HTTP error status response in the period
  • event_summary.total_successful — number of unique URLs with HTTP success status response in the period
  • event_summary.total_fail_ratio — percent of unique URLs with HTTP error status response in the period, which is: event_summary.total_failed / (event_summary.total_failed + event_summary.total_successful)
  • weighted_anomaly_score — net score based on weighted rating of successful versus failed attempts (scanning, login, or other). Scores greater than upper threshold are potentially malicious and less than lower threshold are benign.
  • srcip_host — host name of corresponding source IP address
  • dstip_host — host name of corresponding destination IP address
  • srcip_geo.countryName — source country name

Use Case with Data Points

For every unique URL browsed by each source IP address (srcip), the number of HTTP response failures and successes is calculated periodically. If the number of failures is significantly larger than the number of successes, an alert is triggered. The Interflow includes the source host (srcip_host), destination host (dstip_host), and source country (srcip_geo.countryName).

...

Stellar Cyber reports both internal and external versions of some alerts, with different analysis and recommended actions for each. Similarly, IDS signatures report the direction of data flow as inbound or outbound. Use the following as a guide for these concepts:

  • Addresses with a srcip_type or dstip_type of private are identified as internal. All other values are identified as external (when applicable; not all alerts have unique analytics for internal/external).
  • Communications between hosts where srcip_type and dstip_type are both private are considered internal communications.
  • When an anomaly is observed on an internal communication, the attack is considered to be internal.
  • Stellar Cyber always sets the srcip in the Interflow record as the initiating IP address of an event. Note that IDS signatures, which are reported with relevant alerts, instead list addresses based on the direction of data flow, not the initiating address. So an INBOUND data flow may show the dstip as the source address and the srcip as the destination address, even though the srcip was the initiator of the request. Use INBOUND and OUTBOUND information in the signature to understand the direction of data flow, together with Stellar Cyber’s Interflow record of srcip and dstip to understand which address initiated the threat event.

Unsupervised

N

External User Agent Anomaly

An HTTP connection was made by a user agent that has never been seen before (or been seen very rarely). Investigate the connection destination.

XDR Kill Chain

  • Kill Chain Stage: Initial Attempts

  • Tactic: [External] XDR NBA (XTA0002)

  • Technique: XDR User Agent Anomaly (XT2012)

  • Tags: [External; Network Traffic Analysis]

Event Name

The xdr_event.name for this alert type in the Interflow data is external_user_agent_anomaly.

Severity

30

Key Fields and Relevant Data Points

  • metadata.request.user_agent — user agent in the HTTP connection request  
  • days_silent — number of days since this user agent was last seen
  • srcip_host — host name of corresponding source IP address
  • dstip_host — host name of corresponding destination IP address
  • appid_name — application name

Use Case with Data Points

All user agent (metadata.request.user_agent) HTTP connections having names that do not begin with "Mozilla" or "Aella" are examined. An alert is triggered if any of those agents have not been seen by Stellar Cyber before or have been silent for many days (days_silent). The Interflow includes all information from the suspicious HTTP connection, such as the application (appid_name), the source (srcip_host), and the destination (dstip_host).

...

Stellar Cyber reports both internal and external versions of some alerts, with different analysis and recommended actions for each. Similarly, IDS signatures report the direction of data flow as inbound or outbound. Use the following as a guide for these concepts:

  • Addresses with a srcip_type or dstip_type of private are identified as internal. All other values are identified as external (when applicable; not all alerts have unique analytics for internal/external).
  • Communications between hosts where srcip_type and dstip_type are both private are considered internal communications.
  • When an anomaly is observed on an internal communication, the attack is considered to be internal.
  • Stellar Cyber always sets the srcip in the Interflow record as the initiating IP address of an event. Note that IDS signatures, which are reported with relevant alerts, instead list addresses based on the direction of data flow, not the initiating address. So an INBOUND data flow may show the dstip as the source address and the srcip as the destination address, even though the srcip was the initiator of the request. Use INBOUND and OUTBOUND information in the signature to understand the direction of data flow, together with Stellar Cyber’s Interflow record of srcip and dstip to understand which address initiated the threat event.

Unsupervised

Y

External User Application Usage Anomaly

A user who typically uses a small, consistent number of applications used a new application. Investigate the application, to see if it is benign. Check with the user to see if this was expected.

XDR Kill Chain

  • Kill Chain Stage: Initial Attempts

  • Tactic: [External] XDR UBA (XTA0004)

  • Technique: XDR App Anomaly (XT2003)

  • Tags: [External; User Behavior Analytics]

Event Name

The xdr_event.name for this alert type in the Interflow data is external_user_uncommon_app.

Severity

15

Key Fields and Relevant Data Points

  • srcip_usersid — source user ID  
  • appid_name — application name 
  • srcip_host — host name of corresponding source IP address
  • dstip_host — host name of corresponding destination IP address
  • appid_family — application family
  • srcip_username — source user name
  • stability — score measuring the time since the last new application was used
  • days_stable — time since the last new application was used
  • diversity — score measuring the number of applications that the user used
  • child_count — number of applications that the user used

Use Case with Data Points

An alert is triggered under the following conditions:

  • a user (srcip_usersid, srcip_username) with a small number of applications (diversity, child_count) who has not used a new application for a long period of time (stability, days_stable), and then

  • a new application (appid_name) belonging to an application family (appid_family) appears on a host (scrip_host) with this user, and

  • that host connects to another host (scrip_host)

...

Stellar Cyber reports both internal and external versions of some alerts, with different analysis and recommended actions for each. Similarly, IDS signatures report the direction of data flow as inbound or outbound. Use the following as a guide for these concepts:

  • Addresses with a srcip_type or dstip_type of private are identified as internal. All other values are identified as external (when applicable; not all alerts have unique analytics for internal/external).
  • Communications between hosts where srcip_type and dstip_type are both private are considered internal communications.
  • When an anomaly is observed on an internal communication, the attack is considered to be internal.
  • Stellar Cyber always sets the srcip in the Interflow record as the initiating IP address of an event. Note that IDS signatures, which are reported with relevant alerts, instead list addresses based on the direction of data flow, not the initiating address. So an INBOUND data flow may show the dstip as the source address and the srcip as the destination address, even though the srcip was the initiator of the request. Use INBOUND and OUTBOUND information in the signature to understand the direction of data flow, together with Stellar Cyber’s Interflow record of srcip and dstip to understand which address initiated the threat event.

Unsupervised

Y

External User Data Volume Anomaly

A user had an anomalously large volume of traffic compared to its typical volume or that of its peers. Investigate the user to determine if this is expected.

Firewall and non-firewall data do not contribute to the same alert, so this alert will have either entirely firewall data or no firewall data.

XDR Kill Chain

  • Kill Chain Stage: Initial Attempts

  • Tactic: [External] XDR UBA (XTA0004)

  • Technique: XDR Bytes Anomaly (XT3001)

  • Tags: [External; User Behavior Analytics]

Event Name

The xdr_event.name for this alert type in the Interflow data is external_user_bytes_sum.

Severity

30

Key Fields and Relevant Data Points

  • srcip_usersid — source user ID  
  • actual — actual traffic volume in the period
  • typical — typical traffic volume from the user
  • srcip_host — host name of corresponding source IP address
  • srcip_username — source user name
  • dstip_host — host name of corresponding destination IP address
  • dstip_reputation — destination reputation
  • dstip_geo.countryName — destination country
  • appid_name — application name

Use Case with Data Points

The total traffic volume of each user identified by user ID (scrip_usersid) is calculated periodically. If the volume in one period (actual) is much larger than its normal volume (typical), an alert is triggered.

The Interflow includes the source IP address (scrip_host), destination IP address (dstip_host), destination reputation (dstip_reputation), destination country (dstip_geo.countryName), and application of the traffic (appid_name).

...

Stellar Cyber reports both internal and external versions of some alerts, with different analysis and recommended actions for each. Similarly, IDS signatures report the direction of data flow as inbound or outbound. Use the following as a guide for these concepts:

  • Addresses with a srcip_type or dstip_type of private are identified as internal. All other values are identified as external (when applicable; not all alerts have unique analytics for internal/external).
  • Communications between hosts where srcip_type and dstip_type are both private are considered internal communications.
  • When an anomaly is observed on an internal communication, the attack is considered to be internal.
  • Stellar Cyber always sets the srcip in the Interflow record as the initiating IP address of an event. Note that IDS signatures, which are reported with relevant alerts, instead list addresses based on the direction of data flow, not the initiating address. So an INBOUND data flow may show the dstip as the source address and the srcip as the destination address, even though the srcip was the initiator of the request. Use INBOUND and OUTBOUND information in the signature to understand the direction of data flow, together with Stellar Cyber’s Interflow record of srcip and dstip to understand which address initiated the threat event.

Unsupervised

Y

External User Login Failure Anomaly

An anomalous number of login failures was observed for one of the following applications: SSH, SMTP, FTP, RDP, SMB, databases, Active Directory, Office 365, Okta, AWS CloudTrail, or Google Workspace. For Okta, an anomalous number of multi-factor authentication (MFA) failures was observed. Check with the user.

This alert type has a relatively long detection delay of up to 40 minutes because it waits for login events from high latency data sources and is sensitive to the event order of user logins.

XDR Kill Chain

  • Kill Chain Stage: Initial Attempts

  • Tactic: [External] Credential Access (TA0006 )

  • Technique: Brute Force (T1110 )

  • Tags: [External]

Event Name

The xdr_event.name for this alert type in the Interflow data is external_user_login_fail.

Severity

30

Key Fields and Relevant Data Points

  • srcip — source IP address  
  • dstip — destination IP address  
  • dstip_host — destination host name
  • event_summary.total_failed — number of failed logins in the period
  • event_summary.total_successful — number of successful logins in the period
  • event_summary.total_fail_ratio — percent of failed logins in the period, which is: event_summary.total_failed / (event_summary.total_failed + event_summary.total_successful)
  • weighted_anomaly_score — net score based on weighted rating of successful versus failed attempts (scanning, login, or other). Scores greater than upper threshold are potentially malicious and less than lower threshold are benign.
  • login_type — type of login, such as ssh_traffic, okta_log, or aws_cloudtrail
  • srcip_host — source host name
  • srcip_reputation — source reputation

Use Case with Data Points

Login failures and successes are calculated periodically for every source (srcip) and destination (dstip) IP address. If the number of failures is significantly larger than the number of successes, an alert is triggered. The Interflow includes the login type (login_type), source host (srcip_host), and source reputation (srcip_reputation).

...

Stellar Cyber reports both internal and external versions of some alerts, with different analysis and recommended actions for each. Similarly, IDS signatures report the direction of data flow as inbound or outbound. Use the following as a guide for these concepts:

  • Addresses with a srcip_type or dstip_type of private are identified as internal. All other values are identified as external (when applicable; not all alerts have unique analytics for internal/external).
  • Communications between hosts where srcip_type and dstip_type are both private are considered internal communications.
  • When an anomaly is observed on an internal communication, the attack is considered to be internal.
  • Stellar Cyber always sets the srcip in the Interflow record as the initiating IP address of an event. Note that IDS signatures, which are reported with relevant alerts, instead list addresses based on the direction of data flow, not the initiating address. So an INBOUND data flow may show the dstip as the source address and the srcip as the destination address, even though the srcip was the initiator of the request. Use INBOUND and OUTBOUND information in the signature to understand the direction of data flow, together with Stellar Cyber’s Interflow record of srcip and dstip to understand which address initiated the threat event.

Unsupervised

N

File Action Anomaly

Actions, such as move, copy, delete, or change attribute, were taken on a file or files an anomalous number of times. Investigate the actions and the user to see if this is expected.

XDR Kill Chain

  • Kill Chain Stage: Exfiltration & Impact

  • Tactic: Impact (TA0040 )

  • Technique: Data Manipulation (T1565 )

  • Tags: []

Event Name

The xdr_event.name for this alert type in the Interflow data is anomalous_file_action.

Severity

70

Key Fields and Relevant Data Points

  • secondary — user name  
  • actual — actual number of file actions in the period
  • typical — typical number of file actions in the period
  • path — path to the file

Use Case with Data Points

The number of file actions for each user (secondary) is calculated periodically. If the volume (actual) is anomalous compared to the typical volume (typical) of file actions in any period, an alert is triggered. The Interflow includes the directory to the file (path).

Unsupervised

Y

File Creation Anomaly

A file or files were created an anomalously large number of times. Check with the user to see if this is expected.

XDR Kill Chain

  • Kill Chain Stage: Persistent Foothold

  • Tactic: XDR EBA (XTA0001)

  • Technique: XDR File Anomaly (XT1003)

  • Tags: []

Event Name

The xdr_event.name for this alert type in the Interflow data is file_creation.

Severity

70

Key Fields and Relevant Data Points

  • secondary — user name  
  • actual — actual number of file creations in the period
  • typical — typical number of file creations in the period
  • path — path to the file(s) created

Use Case with Data Points

The number of file creations for each user (command) is calculated periodically. If the volume (actual) is much larger than the typical volume (typical) of file creations in any period, an alert is triggered. The Interflow includes the directory to the file (path).

Unsupervised

Y

Google Workspace Account Manipulation

A Google Workspace user was manipulated. Check with the user to make sure this was expected.

XDR Kill Chain

  • Kill Chain Stage: Initial Attempts

  • Tactic: [External] XDR UBA (XTA0004)

  • Technique: XDR Account Anomaly (XT4007)

  • Tags: [External]

Event Name

The xdr_event.name for this alert type in the Interflow data is gsuite_account_manipulation.

Severity

70

Key Fields and Relevant Data Points

  • event_detail.affected_email_address — key ID for the account  
  • event_detail.name — Google Workspace suspicious event name
  • event_detail.type — Google Workspace suspicious event type

Use Case with Data Points

For each Google Workspace account (event_detail.affected_email_address), account manipulation is evaluated periodically. This alert is triggered if the Google Security center reports a leaked password or a user account being suspended for specific reasons. The Interflow includes the account ID (event_detail.affected_email_address), Google Workspace event name (event_detail.name), and Google Workspace event type (event_detail.type).

Analytics

N

Google Workspace Attack Warning

Attacks to a Google Workspace account were observed. Check with the account holder.

XDR Kill Chain

  • Kill Chain Stage: Initial Attempts

  • Tactic: [External] Credential Access (TA0006 )

  • Technique: Brute Force (T1110 )

  • Tags: [External]

Event Name

The xdr_event.name for this alert type in the Interflow data is gsuite_attack_warning.

Severity

74

Key Fields and Relevant Data Points

  • gsuite.actor.email — key ID for the account  
  • srcip — source IP address
  • srcip_host — source host name
  • event_detail.name — Google Workspace suspicious event name
  • event_detail.type — Google Workspace suspicious event type

Use Case with Data Points

For each Google Workspace account (actor.email), attacks are searched periodically. If an attack is identified, an alert is triggered. The Interflow includes the account ID (actor.email), source IP address (srcip), Google Workspace event name (event_detail.name), and Google Workspace event type (event_detail.type).

Analytics

N

Google Workspace Suspicious Activities

Suspicious activities were observed in a Google Workspace account. Check with the account holder.

XDR Kill Chain

  • Kill Chain Stage: Initial Attempts

  • Tactic: [External] XDR UBA (XTA0004)

  • Technique: XDR Login Anomaly (XT4006)

  • Tags: [External]

Event Name

The xdr_event.name for this alert type in the Interflow data is gsuite_suspicious_activities.

Severity

50

Key Fields and Relevant Data Points

  • gsuite.actor.email — key ID for the account  
  • srcip — source IP address
  • srcip_host — source host name
  • event_detail.name — Google Workspace suspicious event name
  • event_detail.type — Google Workspace suspicious event type

Use Case with Data Points

For each Google Workspace account (actor.email), suspicious activities are searched periodically. If suspicious activities are detected, an alert is triggered. The Interflow includes the account ID (actor.email), source IP address (srcip), Google Workspace event name (event_detail.name), and Google Workspace event type (event_detail.type).

Analytics

N

Google Workspace User Suspended

A Google Workspace user was suspended. Check with the user to make sure this was expected.

XDR Kill Chain

  • Kill Chain Stage: Initial Attempts

  • Tactic: [External] XDR UBA (XTA0004)

  • Technique: XDR Account Anomaly (XT4007)

  • Tags: [External]

Event Name

The xdr_event.name for this alert type in the Interflow data is gsuite_user_suspended.

Severity

70

Key Fields and Relevant Data Points

  • gsuite.actor.email — key ID for the account  
  • srcip — source IP address
  • srcip_host — source host name
  • event_detail.name — Google Workspace suspicious event name
  • event_detail.type — Google Workspace suspicious event type

Use Case with Data Points

For each Google Workspace account (actor.email), suspension status is searched periodically. If a user is suspended, an alert is triggered. The Interflow includes the account ID (actor.email), source IP address (srcip), Google Workspace event name (event_detail.name), and Google Workspace event type (event_detail.type).

Analytics

N

Hydra Password Guessing Hack Tool

A user on a Windows host executed a command-line script that launched either the hydra.exe command or a command using known Hydra style parameters, which may be an inappropriate use of the Hydra password guessing tool.

XDR Kill Chain

  • Kill Chain Stage: Propagation

  • Tactic: [Internal] Credential Access (TA0006 )

  • Technique: Brute Force (T1110 )

  • Tags: [Hydra]

Event Name

The xdr_event.name for this alert type in the Interflow data is hydra_password_guessing_hack_tool.

Severity

90

Key Fields and Relevant Data Points

  • hostip — device internal IP address  
  • event_data.Image — process running hydra.exe for password cracking.  
  • event_data.CommandLine — command used to run the tool  
  • computer_name — name of the Windows host

Use Case with Data Points

This alert is triggered if a Windows host (hostip) executes a PowerShell script with a context that includes one or more flags (event_data.Imageor event_data.CommandLine indicating usage of the Hydra password guessing hack tool. The Interflow includes the IP address of the Windows host (hostip), the host name (computer_name), and the script image (event_data.Image) or script payload (event_data.CommandLine).

Validation / Remediation

Check the body of the Powershell script that is reported on the Windows host to identify whether the contents of the script are actually malicious. If malicious, consider quarantining the host.

Potential False Positives

The running of any executable named hydra.exe or a command that has parameters of -u and -p or ^user^ and ^pass^ triggers this alert.

Analytics

N

Impossible Travel Anomaly

A user logged in from locations that are geographically impossible to travel between in the time frame. Check with the user.

This alert type has a relatively long detection delay of up to 40 minutes because it waits for login events from high latency data sources and is sensitive to the event order of user logins.

XDR Kill Chain

  • Kill Chain Stage: Initial Attempts

  • Tactic: [External] XDR UBA (XTA0004)

  • Technique: XDR Location Anomaly (XT2001)

  • Tags: [User Behavior Analytics]

Event Name

The xdr_event.name for this alert type in the Interflow data is user_impossible_travel.

Severity

60

Key Fields and Relevant Data Points

  • srcip_usersid — key ID for the source user 
  • srcip_username — source user name
  • srcip — source IP address
  • srcip_host — source host name
  • srcip_geo — source IP address geo location, including latitude and longitude
  • distance_deviation — deviation in distance (miles) between the two login locations
  • time_deviation — deviation in time (seconds) between the two login events
  • travel_speed — calculated speed for the user to travel between the two location (miles/hour)
  • appid_name — application name for the login event
  • last_login_time — time of 2nd login, event 2 (E2)
  • _id2 — ID of E2
  • _index2 — index of E2
  • srcip2 — source IP address of E2
  • srcip_geo2 — source IP address geo location of E2, including latitude and longitude
  • engid_gateway — gateway IP address, used to determine geo location when source IP address is private

Use Case with Data Points

Login events (E1 and E2) are examined for a user (srcip_usersid), to see if the login locations (srcip_geo and srcip_geo2), that are at least 100 miles apart, changed faster (travel_speed = distance_deviation/time_deviation) than possible with the typical commercial flight speed of 600 miles/hour.

E1 is the basis for the Interflow. The srcip_usersid and srcip_username identify the user, appid_name identifies the application, and last_login_time identifies the time when the 2nd login event happened. You can find detailed information about E2 by checking id2 in index2, source IP (srcip2), and geo location (srcip_geo2).

Unsupervised

Y

Internal Account Login Failure Anomaly

An anomalously large number of login failures from an internal source IP address to an internal destination IP address was observed for an account. Check with the user.

This alert type has a relatively long detection delay of up to 40 minutes because it waits for login events from high latency data sources and is sensitive to the event order of user logins.

XDR Kill Chain

  • Kill Chain Stage: Propagation

  • Tactic: [Internal] Credential Access (TA0006 )

  • Technique: Brute Force (T1110 )

  • Tags: [Internal]

Event Name

The xdr_event.name for this alert type in the Interflow data is internal_cloud_account_login_failure.

Severity

60

Key Fields and Relevant Data Points

  • srcip_usersid — account user ID  

    or

  • srcip_username — account user name, enriched from event_data.targetusername  

    The key field for this alert type can be either srcip_usersid or srcip_username, depending on the data feed.

  • event_summary.total_failed — number of failed logins in the period
  • event_summary.total_successful — number of successful logins in the period
  • event_summary.total_fail_ratio — percent of failed logins in the period, which is: event_summary.total_failed / (event_summary.total_failed + event_summary.total_successful)
  • weighted_anomaly_score — net score based on weighted rating of successful versus failed attempts (scanning, login, or other). Scores greater than upper threshold are potentially malicious and less than lower threshold are benign.
  • srcip_host — host name of corresponding source IP address
  • login_type — type of login
  • srcip_reputation — source reputation

Use Case with Data Points

Login failures and successes between any internal IP addresses are calculated periodically for every account (srcip_usersid). If the number of failures is significantly larger than the number of successes, an alert is triggered. A sample Interflow includes the login type (login_type), source host (srcip_host), and source reputation (srcip_reputation).

...

Stellar Cyber reports both internal and external versions of some alerts, with different analysis and recommended actions for each. Similarly, IDS signatures report the direction of data flow as inbound or outbound. Use the following as a guide for these concepts:

  • Addresses with a srcip_type or dstip_type of private are identified as internal. All other values are identified as external (when applicable; not all alerts have unique analytics for internal/external).
  • Communications between hosts where srcip_type and dstip_type are both private are considered internal communications.
  • When an anomaly is observed on an internal communication, the attack is considered to be internal.
  • Stellar Cyber always sets the srcip in the Interflow record as the initiating IP address of an event. Note that IDS signatures, which are reported with relevant alerts, instead list addresses based on the direction of data flow, not the initiating address. So an INBOUND data flow may show the dstip as the source address and the srcip as the destination address, even though the srcip was the initiator of the request. Use INBOUND and OUTBOUND information in the signature to understand the direction of data flow, together with Stellar Cyber’s Interflow record of srcip and dstip to understand which address initiated the threat event.

Unsupervised

N

Internal Brute-Forced Successful User Login

A successful login was observed from an IP address that had previously seen a large number of login failures, or a successful login to a user account was observed from another IP address or IP addresses that had previously seen a large number of login failures to that account. Check with the user.

This alert type has two subtypes:

This alert type has a relatively long detection delay of up to 40 minutes because it waits for login events from high latency data sources and is sensitive to the event order of user logins.

XDR Kill Chain

  • Kill Chain Stage: Propagation

  • Tactic: [Internal] Credential Access (TA0006 )

  • Technique: Brute Force (T1110 )

  • Tags: [Internal]

Event Name

The xdr_event.name for this alert type in the Interflow data is internal_user_success_brute_forcer.

Severity

95

Alert Subtype: Source IP-Based

The source IP-based alert subtype has the same XDR Kill Chain and Event Name as the user ID-based alert subtype, but differs in the Key Fields and Relevant Data Points and Use Case with Data Points.

Key Fields and Relevant Data Points

  • srcip — source IP address  
  • srcip_usersid — Windows SID associated with the source IP address
  • srcip_host — source host name
  • srcip_reputation — source reputation
  • source_geo.countryName — source country
  • dstip_host — destination host name
  • login_type — type of login
  • username — user name
  • related_alert._id — link to the related Internal User Login Failure Anomaly

Use Case with Data Points

The login records to an internal IP address (dstip) are checked for every internal source IP address (srcip). An alert is triggered if that IP address:

  1. Has so many failed login attempts that it triggered the Internal User Login Failure Anomaly, and

  2. Had a successful login

A sample Interflow includes the source IP address (srcip), login type (login_type), source host name (srcip_host), source reputation (srcip_reputation), source country (srcip_geo.countryName), and user name (username).

Alert Subtype: User ID-Based

The user ID-based alert subtype has the same XDR Kill Chain and Event Name as the source IP-based alert subtype, but differs in the Key Fields and Relevant Data Points and Use Case with Data Points.

Key Fields and Relevant Data Points

  • srcip — source IP address
  • srcip_usersid — Windows SID associated with the source IP address 
  • srcip_host — source host name
  • srcip_reputation — source reputation
  • source_geo.countryName — source country
  • dstip_host — destination host name
  • login_type — type of login
  • username — user name
  • related_alert._id — link to the related Internal Account Login Failure Anomaly

Use Case with Data Points

The login records to a user account (srcip_usersid) are checked for every internal source IP address (srcip). An alert is triggered if that user account:

  1. Has so many failed login attempts that it triggered the Internal Account Login Failure Anomaly, and

  2. Had a successful login

A sample Interflow includes the source IP address (srcip), login type (login_type), source host name (srcip_host), source reputation (srcip_reputation), source country (srcip_geo.countryName), and user name (username).

...

Stellar Cyber reports both internal and external versions of some alerts, with different analysis and recommended actions for each. Similarly, IDS signatures report the direction of data flow as inbound or outbound. Use the following as a guide for these concepts:

  • Addresses with a srcip_type or dstip_type of private are identified as internal. All other values are identified as external (when applicable; not all alerts have unique analytics for internal/external).
  • Communications between hosts where srcip_type and dstip_type are both private are considered internal communications.
  • When an anomaly is observed on an internal communication, the attack is considered to be internal.
  • Stellar Cyber always sets the srcip in the Interflow record as the initiating IP address of an event. Note that IDS signatures, which are reported with relevant alerts, instead list addresses based on the direction of data flow, not the initiating address. So an INBOUND data flow may show the dstip as the source address and the srcip as the destination address, even though the srcip was the initiator of the request. Use INBOUND and OUTBOUND information in the signature to understand the direction of data flow, together with Stellar Cyber’s Interflow record of srcip and dstip to understand which address initiated the threat event.

Unsupervised+Analytics

N

Internal Credential Stuffing

An anomalously large amount of username/password testing was observed on an internal Windows authentication service. Check the activity after successful logins, and consider blocking the internal source IP addresses.

XDR Kill Chain

  • Kill Chain Stage: Propagation

  • Tactic: [Internal] Credential Access (TA0006 )

  • Technique: Brute Force (T1110 )

  • Tags: [Internal]

Event Name

The xdr_event.name for this alert type in the Interflow data is internal_credential_stuffing.

Severity

75

Key Fields and Relevant Data Points

  • msg_class — Microsoft-Windows-Security-Auditing for Windows  
  • service_id — specific account ID of a service  
  • login_failure_rate — rate of login failures per minute in the period
  • unknown_users_rate — rate of unknown user names per minute in the period
  • unknown_users_to_login_failures — ratio of unknown user names to login failures in the period
  • suspicious_ips — suspicious source IP addresses (up to 100)
  • possible_breached_ips — list of malicious IP addresses that may have successful breach activities

Use Case with Data Points

Internal credential stuffing is the constant testing of username/password combinations on the AWS, Okta, or Windows authentication functions. Login activity is monitored and if the number of failed logins is larger than normal for that service, an alert is triggered. The Interflow includes the service (msg_class), tenant's account ID on that service (service_id), suspicious source IP address (suspicious_ips), login failure rate (login_failure_rate), unknown user rate (unknown_users_rate), the ratio of unknown users to login failures (unknown_users_to_login_failures), and a list of source IP addresses that might have suspicious activities and should be investigated (possible_breached_ips).

...

Stellar Cyber reports both internal and external versions of some alerts, with different analysis and recommended actions for each. Similarly, IDS signatures report the direction of data flow as inbound or outbound. Use the following as a guide for these concepts:

  • Addresses with a srcip_type or dstip_type of private are identified as internal. All other values are identified as external (when applicable; not all alerts have unique analytics for internal/external).
  • Communications between hosts where srcip_type and dstip_type are both private are considered internal communications.
  • When an anomaly is observed on an internal communication, the attack is considered to be internal.
  • Stellar Cyber always sets the srcip in the Interflow record as the initiating IP address of an event. Note that IDS signatures, which are reported with relevant alerts, instead list addresses based on the direction of data flow, not the initiating address. So an INBOUND data flow may show the dstip as the source address and the srcip as the destination address, even though the srcip was the initiator of the request. Use INBOUND and OUTBOUND information in the signature to understand the direction of data flow, together with Stellar Cyber’s Interflow record of srcip and dstip to understand which address initiated the threat event.

Unsupervised

N

Internal Exploited Vulnerability

An internal host with a vulnerability discovered by a security scanning tool was exploited by an attack on that same vulnerability, indicating a high probability of success. Check the target to see if it was compromised.

XDR Kill Chain

  • Kill Chain Stage: Exploration

  • Tactic: [Internal] XDR NBA (XTA0002)

  • Technique: XDR Exploited Vulnerability (XT2015)

  • Tags: [Internal; Network Traffic Analysis]

Event Name

The xdr_event.name for this alert type in the Interflow data is internal_vuln_exploit_correlation.

Severity

75

Key Fields and Relevant Data Points

  • tenantid — tenant ID
  • vulnerability_id — ID of the original security scan result
  • ids_event_id — ID of the original IDS exploit event
  • srcip (of security scan result) — IP address of the target correlation_info.srcip
  • dstip (of IDS event) — IP address of the target (correlation_info.dstip)
  • srcip (of IDS event) — IP address of the attacker (correlation_info.srcip)
  • correlation_info.vulnerability.cve — CVE associated with the reported vulnerability
  • correlation_info.ids.cve — CVE the attacker used to exploit the host

Use Case with Data Points

An attacker (srcip) with IP address A is performing an exploit against a target (dstip) with IP address B using a vulnerability (ids.cve) with CVE x. If any security scanning tool found the target (srcip) with IP address B to have a vulnerability (vulnerability.cve) with CVE x, an alert is triggered.

When an alert is triggered, a new correlation event is generated. The Interflow of the correlation event includes the ID of the IDS exploit event (ids_event_id), the ID of the security scan record (vulnerability_id), the IP address of the attacker (correlation_info.srcip of the IDS event), the IP address of the victim (correlation_info.dstip of the IDS event or correlation_info.srcip of the security scan record), and the CVE that was used in the exploit (correlation_info.vulnerability.cve and correlation_info.ids.cve).

...

Stellar Cyber reports both internal and external versions of some alerts, with different analysis and recommended actions for each. Similarly, IDS signatures report the direction of data flow as inbound or outbound. Use the following as a guide for these concepts:

  • Addresses with a srcip_type or dstip_type of private are identified as internal. All other values are identified as external (when applicable; not all alerts have unique analytics for internal/external).
  • Communications between hosts where srcip_type and dstip_type are both private are considered internal communications.
  • When an anomaly is observed on an internal communication, the attack is considered to be internal.
  • Stellar Cyber always sets the srcip in the Interflow record as the initiating IP address of an event. Note that IDS signatures, which are reported with relevant alerts, instead list addresses based on the direction of data flow, not the initiating address. So an INBOUND data flow may show the dstip as the source address and the srcip as the destination address, even though the srcip was the initiator of the request. Use INBOUND and OUTBOUND information in the signature to understand the direction of data flow, together with Stellar Cyber’s Interflow record of srcip and dstip to understand which address initiated the threat event.

Analytics

N

Internal Firewall Denial Anomaly

A internal source host had actions blocked by a firewall too many times. Investigate the firewall rules that were violated. If suspicious, block the internal source IP address.

XDR Kill Chain

  • Kill Chain Stage: Exploration

  • Tactic: [Internal] XDR NBA (XTA0002)

  • Technique: XDR Firewall Anomaly (XT2002)

  • Tags: [Internal; Network Traffic Analysis; Firewall Anomalies]

Event Name

The xdr_event.name for this alert type in the Interflow data is internal_fw_action.

Severity

60

Key Fields and Relevant Data Points

  • srcip_host — source host name 
  • srcip — source IP address
  • actual — actual number of firewall denials in the period
  • typical — typical number of firewall denials in the period
  • dstip_host — host name of corresponding destination IP address
  • dev_name — name of the firewall
  • engid_name — name of the sensor

Use Case with Data Points

The number of firewall denials for every internal source IP address (srcip) is calculated periodically. If an internal source IP address’s number of firewall denials (actual) is much larger than the historical count (typical) of all internal IP addresses, an alert is triggered. The Interflow includes the name of the firewall (dev_name), the name of the sensor (engid_name), and the destination host (dstip_host).

...

Stellar Cyber reports both internal and external versions of some alerts, with different analysis and recommended actions for each. Similarly, IDS signatures report the direction of data flow as inbound or outbound. Use the following as a guide for these concepts:

  • Addresses with a srcip_type or dstip_type of private are identified as internal. All other values are identified as external (when applicable; not all alerts have unique analytics for internal/external).
  • Communications between hosts where srcip_type and dstip_type are both private are considered internal communications.
  • When an anomaly is observed on an internal communication, the attack is considered to be internal.
  • Stellar Cyber always sets the srcip in the Interflow record as the initiating IP address of an event. Note that IDS signatures, which are reported with relevant alerts, instead list addresses based on the direction of data flow, not the initiating address. So an INBOUND data flow may show the dstip as the source address and the srcip as the destination address, even though the srcip was the initiator of the request. Use INBOUND and OUTBOUND information in the signature to understand the direction of data flow, together with Stellar Cyber’s Interflow record of srcip and dstip to understand which address initiated the threat event.

Unsupervised

Y

Internal Firewall Policy Anomaly

A rarely triggered firewall policy involving an internal source IP and internal destination IP has been violated. Investigate that policy and track down the violation.

XDR Kill Chain

  • Kill Chain Stage: Initial Attempts

  • Tactic: [Internal] XDR NBA (XTA0002)

  • Technique: XDR Firewall Anomaly (XT2002)

  • Tags: [Internal; Network Traffic Analysis; Firewall Anomalies]

Event Name

The xdr_event.name for this alert type in the Interflow data is internal_fw_policy_id.

Severity

40

Key Fields and Relevant Data Points

  • fw_policy_id — ID of the violated firewall policy  
  • days_silent — number of days since this firewall policy was last seen
  • srcip_host — host name of corresponding source IP address
  • dstip_host — host name of corresponding destination IP address
  • dev_name — device name
  • dev_type — device type
  • engid_name — sensor name

Use Case with Data Points

A firewall policy violation (fw_policy_id), which is raised by a device (dev_name and dev_type) and captured by a sensor (engid_name), shows never seen or very rare (days_silent) traffic between an internal host (srcip_host) and another internal host (dstip_host). This violation will trigger an alert.

...

Stellar Cyber reports both internal and external versions of some alerts, with different analysis and recommended actions for each. Similarly, IDS signatures report the direction of data flow as inbound or outbound. Use the following as a guide for these concepts:

  • Addresses with a srcip_type or dstip_type of private are identified as internal. All other values are identified as external (when applicable; not all alerts have unique analytics for internal/external).
  • Communications between hosts where srcip_type and dstip_type are both private are considered internal communications.
  • When an anomaly is observed on an internal communication, the attack is considered to be internal.
  • Stellar Cyber always sets the srcip in the Interflow record as the initiating IP address of an event. Note that IDS signatures, which are reported with relevant alerts, instead list addresses based on the direction of data flow, not the initiating address. So an INBOUND data flow may show the dstip as the source address and the srcip as the destination address, even though the srcip was the initiator of the request. Use INBOUND and OUTBOUND information in the signature to understand the direction of data flow, together with Stellar Cyber’s Interflow record of srcip and dstip to understand which address initiated the threat event.

Unsupervised

Y

Internal Handshake Failure

There were too many handshake failures between two internal hosts, which might indicate port scanning. Check the source host to see if this was expected, and if not, consider blocking the host.

XDR Kill Chain

  • Kill Chain Stage: Exploration

  • Tactic: [Internal] Discovery (TA0007 )

  • Technique: Network Service Scanning (T1046 )

  • Tags: [Internal; Network Traffic Analysis]

Event Name

The xdr_event.name for this alert type in the Interflow data is internal_handshake_failure.

Severity

30

Key Fields and Relevant Data Points

  • srcip — source IP address of the host with the handshake failures 
  • srcip_host — source host name
  • dstip — destination IP address of the host with the handshake failures 
  • dstip_host — destination host name
  • timestamp — when the scan happened

Use Case with Data Points

If an internal host (srcip) scans across many ports on another internal host (dstip), an alert is triggered. The Interflow includes the IP address of the potential attacker (srcip), the IP address of the victim (dstip), a special message flag (msgtyp), and when the scan happened (timestamp).

...

Stellar Cyber reports both internal and external versions of some alerts, with different analysis and recommended actions for each. Similarly, IDS signatures report the direction of data flow as inbound or outbound. Use the following as a guide for these concepts:

  • Addresses with a srcip_type or dstip_type of private are identified as internal. All other values are identified as external (when applicable; not all alerts have unique analytics for internal/external).
  • Communications between hosts where srcip_type and dstip_type are both private are considered internal communications.
  • When an anomaly is observed on an internal communication, the attack is considered to be internal.
  • Stellar Cyber always sets the srcip in the Interflow record as the initiating IP address of an event. Note that IDS signatures, which are reported with relevant alerts, instead list addresses based on the direction of data flow, not the initiating address. So an INBOUND data flow may show the dstip as the source address and the srcip as the destination address, even though the srcip was the initiator of the request. Use INBOUND and OUTBOUND information in the signature to understand the direction of data flow, together with Stellar Cyber’s Interflow record of srcip and dstip to understand which address initiated the threat event.

Analytics

N

Internal IDS Signature Spike

A source IP address transmitted an anomalous number of different IDS signatures. Typically, this indicates host penetration or vulnerability scanning.

XDR Kill Chain

  • Kill Chain Stage: Propagation

  • Tactic: Lateral Movement (TA0008 )

  • Technique: Exploitation of Remote Services (T1210 )

  • Tags: [Internal; Network Traffic Analysis]

Event Name

The xdr_event.name for this alert type in the Interflow data is internal_ids_signature_spike.

Severity

65

Key Fields and Relevant Data Points

  • srcip — source IP address 
  • ids_signatures_summarize — summarized IDS signatures
  • srcip_host — source host name
  • actual — actual number of unique IDS signatures in the period, with critical IDS signatures counted as 2, high counted as 1, low counted as 0.5, and others counted as 1
  • typical — typical number of unique IDS signatures from the source IP address, with critical IDS signatures counted as 2, high counted as 1, low counted as 0.5, and others counted as 1

Use Case with Data Points

The number of unique IDS signatures (ids.signature) and severity (ids.severity), are calculated periodically. If many different exploits with unique IDS signatures are observed, an alert is triggered. The Interflow includes a source (srcip), timestamp, an accumulated severity of IDS signatures (actual), the usual accumulated severity of IDS signatures (typical), and a sampling of the IDS signatures used in the attack (ids_signatures_summarize).

...

Stellar Cyber reports both internal and external versions of some alerts, with different analysis and recommended actions for each. Similarly, IDS signatures report the direction of data flow as inbound or outbound. Use the following as a guide for these concepts:

  • Addresses with a srcip_type or dstip_type of private are identified as internal. All other values are identified as external (when applicable; not all alerts have unique analytics for internal/external).
  • Communications between hosts where srcip_type and dstip_type are both private are considered internal communications.
  • When an anomaly is observed on an internal communication, the attack is considered to be internal.
  • Stellar Cyber always sets the srcip in the Interflow record as the initiating IP address of an event. Note that IDS signatures, which are reported with relevant alerts, instead list addresses based on the direction of data flow, not the initiating address. So an INBOUND data flow may show the dstip as the source address and the srcip as the destination address, even though the srcip was the initiator of the request. Use INBOUND and OUTBOUND information in the signature to understand the direction of data flow, together with Stellar Cyber’s Interflow record of srcip and dstip to understand which address initiated the threat event.

Unsupervised

Y

Internal IP / Port Scan Anomaly

A host has either generated an anomalous number of connections compared to the typical amount, or has triggered an anomalous number of connection failure responses, in the measured interval. This can indicate that an attacker is scanning for computers or ports to exploit. Check with the user.

This alert type has two subtypes:

Alert Subtype: Connection Failure Anomaly (Sensor Traffic)

XDR Kill Chain

  • Kill Chain Stage: Exploration

  • Tactic: [Internal] Discovery (TA0007 )

  • Technique: Network Service Scanning (T1046 )

  • Tags: [Internal; Network Traffic Analysis]

Event Name

The xdr_event.name for this alert type in the Interflow data is internal_port_scan.

Severity

40

Key Fields and Relevant Data Points

  • srcip — source IP address  
  • srcip_host — host name of corresponding source IP address
  • num_failed — unique number of (destination IP and destination port) tuples that respond with failed status
  • num_successful — unique number of (destination IP and destination port) tuples that respond with success status
  • percent_failed — percent of unique (destination IP and destination port) tuples that respond with failed status
  • weighted_anomaly_score — net score based on weighted rating of successful versus failed attempts (scanning, login, or other). Scores greater than upper threshold are potentially malicious and less than lower threshold are benign.
  • dstip_host — host name of corresponding destination IP address
  • appid_name — application name

Use Case with Data Points

For each internal source IP address (srcip), the number of unique internal destination IP:port pairs that gave fail responses and the number of unique destination IP:port pairs that gave success responses are calculated periodically. If the number of failures is significantly larger than the number of successes, an alert is triggered. The Interflow includes the source host (srcip_host), destination host (dstip_host), and application name (appid_name).

Validation / Remediation

Check with the user related to the internal source IP address. Inform the user's supervisor if the activity is unauthorized.

Potential False Positives

Some legitimate activities such as vulnerability scans or penetration testing may trigger this alert type.

Alert Subtype: Connection Spike Anomaly (Firewall / Windows Traffic)

XDR Kill Chain

  • Kill Chain Stage: Exploration

  • Tactic: [Internal] Discovery (TA0007 )

  • Technique: Network Service Scanning (T1046 )

  • Tags: [Internal; Network Traffic Analysis]

Event Name

The xdr_event.name for this alert type in the Interflow data is internal_port_scan_tsa.

Severity

40

Key Fields and Relevant Data Points

  • srcip — source IP address  
  • srcip_host — host name of corresponding source IP address
  • actual — actual number of connections to the destination IP address in the period
  • typical — typical number of connections to the destination IP address
  • dstip_host — host name of corresponding destination IP address
  • appid_name — application name

Use Case with Data Points

For every unique triplet (source IP address, destination IP address, and destination port) browsed by each source IP address (srcip), the number of response failures and successes and the number of total data volume are calculated periodically. If the number of failures is significantly larger than the number of successes, or the total data volume is significantly larger than the typical number, an alert is triggered. The Interflow includes the source host (srcip_host), destination host (dstip_host), and application name (appid_name).

Considering that a lateral scan (private to private) is more sensitive than a non-lateral scan, this alert type is divided into two parts. One focuses on lateral scan analysis, the other focuses on non-lateral scan analysis. The mechanism remains the same as before, with the trigger condition for lateral scan alert being more sensitive than non-lateral one.

Validation / Remediation

Check with the user related to the internal source IP address. Inform the user's supervisor if the activity is unauthorized.

Potential False Positives

Some legitimate activities such as vulnerability scans or penetration testing may trigger this alert type.

...

Stellar Cyber reports both internal and external versions of some alerts, with different analysis and recommended actions for each. Similarly, IDS signatures report the direction of data flow as inbound or outbound. Use the following as a guide for these concepts:

  • Addresses with a srcip_type or dstip_type of private are identified as internal. All other values are identified as external (when applicable; not all alerts have unique analytics for internal/external).
  • Communications between hosts where srcip_type and dstip_type are both private are considered internal communications.
  • When an anomaly is observed on an internal communication, the attack is considered to be internal.
  • Stellar Cyber always sets the srcip in the Interflow record as the initiating IP address of an event. Note that IDS signatures, which are reported with relevant alerts, instead list addresses based on the direction of data flow, not the initiating address. So an INBOUND data flow may show the dstip as the source address and the srcip as the destination address, even though the srcip was the initiator of the request. Use INBOUND and OUTBOUND information in the signature to understand the direction of data flow, together with Stellar Cyber’s Interflow record of srcip and dstip to understand which address initiated the threat event.

Unsupervised

Y

Internal Non-Standard Port Anomaly

An application had an anomalously large number of connections or a rarely seen connection to an internal IP address on non-standard ports. Check the application to be sure this is benign.

XDR Kill Chain

  • Kill Chain Stage: Exploration

  • Tactic: [Internal] XDR NBA (XTA0002)

  • Technique: XDR Service on Non-Standard Port (XT2011)

  • Tags: [Internal; Network Traffic Analysis]

Event Name

The xdr_event.name for this alert type in the Interflow data is internal_non_std_port_anomaly.

Severity

20

Key Fields and Relevant Data Points

  • dstip — destination IP address  
  • dstport — destination port  
  • appid — application ID  
  • days_silent — number of days since the application was last seen
  • appid_name — application name
  • dstip_host — host name of corresponding destination IP address
  • actual — actual number of connections in the period
  • typical — typical number of connections in the period

Use Case with Data Points

The number of connections for an application (dst_ip + dstport + appid) to an internal IP address is calculated periodically. If a non-standard combination has an actual number of connections (actual) that is much larger than the typical number of connections (typical), or the combination has not appeared for a long time, an alert is triggered. The Interflow includes the source host (srcip_host), destination IP address (dstip), destination port (dstport), application ID (appid), and application name (appid_name).

...

Stellar Cyber reports both internal and external versions of some alerts, with different analysis and recommended actions for each. Similarly, IDS signatures report the direction of data flow as inbound or outbound. Use the following as a guide for these concepts:

  • Addresses with a srcip_type or dstip_type of private are identified as internal. All other values are identified as external (when applicable; not all alerts have unique analytics for internal/external).
  • Communications between hosts where srcip_type and dstip_type are both private are considered internal communications.
  • When an anomaly is observed on an internal communication, the attack is considered to be internal.
  • Stellar Cyber always sets the srcip in the Interflow record as the initiating IP address of an event. Note that IDS signatures, which are reported with relevant alerts, instead list addresses based on the direction of data flow, not the initiating address. So an INBOUND data flow may show the dstip as the source address and the srcip as the destination address, even though the srcip was the initiator of the request. Use INBOUND and OUTBOUND information in the signature to understand the direction of data flow, together with Stellar Cyber’s Interflow record of srcip and dstip to understand which address initiated the threat event.

Unsupervised

Y

Internal Other Malware

Malware with uncategorized malicious activity in internal traffic was observed. Check with the user.

XDR Kill Chain

  • Kill Chain Stage: Propagation

  • Tactic: [Internal] XDR Malware (XTA0006)

  • Technique: XDR Miscellaneous Malware (XT6001)

  • Tags: [Internal; Malware]

Event Name

The xdr_event.name for this alert type in the Interflow data is internal_malware_activity.

Severity

70

Key Fields and Relevant Data Points

  • ids.signature — IDS signature  
  • maltrace-cloud.data.malicious_activity — malicious activity  
  • actual — number of records for one IDS signature or malicious activity in the period
  • lateral — boolean, indicating whether this activity is lateral (from private to private)
  • srcip_host — source host name
  • srcip_geo.countryName — source country
  • dstip_host — destination host name
  • dstip_geo.countryName — destination country
  • file_name — name of the file that carries the malware
  • event_source — source of the event, either ids or sandbox

Use Case with Data Points

If ML-IDS or sandbox indicates malware in internal traffic that cannot be categorized as ransomware, spyware, trojan, PUA, or adware, an alert is triggered. A sample Interflow includes malicious activity for sandbox (maltrace-cloud.data.malicious_activity), IDS signature for ML-IDS (ids.signature), event source (event_source), source host (srcip_host), source country (srcip_geo.countryName), destination host (dstip_host), destination country (dstip_geo.countryName), and the name of the file that carries the malware (file_name) from the sandbox.

...

Stellar Cyber reports both internal and external versions of some alerts, with different analysis and recommended actions for each. Similarly, IDS signatures report the direction of data flow as inbound or outbound. Use the following as a guide for these concepts:

  • Addresses with a srcip_type or dstip_type of private are identified as internal. All other values are identified as external (when applicable; not all alerts have unique analytics for internal/external).
  • Communications between hosts where srcip_type and dstip_type are both private are considered internal communications.
  • When an anomaly is observed on an internal communication, the attack is considered to be internal.
  • Stellar Cyber always sets the srcip in the Interflow record as the initiating IP address of an event. Note that IDS signatures, which are reported with relevant alerts, instead list addresses based on the direction of data flow, not the initiating address. So an INBOUND data flow may show the dstip as the source address and the srcip as the destination address, even though the srcip was the initiator of the request. Use INBOUND and OUTBOUND information in the signature to understand the direction of data flow, together with Stellar Cyber’s Interflow record of srcip and dstip to understand which address initiated the threat event.

Analytics

N

Internal Password Spraying

An anomalously large number of failed logins with unknown user names was observed on internal Windows authentication services. Check the activity after successful logins, and consider blocking the internal source IP addresses.

XDR Kill Chain

  • Kill Chain Stage: Propagation

  • Tactic: Credential Access (TA0006 )

  • Technique: Brute Force (T1110 )

  • Sub-technique: Password Spraying (T1110.003 )

  • Tags: [Internal]

Event Name

The xdr_event.name for this alert type in the Interflow data is internal_password_spray.

Severity

75

Key Fields and Relevant Data Points

  • srcip — source IP address generating a failed login 

    or

  • event_data.Workstation — workstation generating a failed login 

    The key field for this alert type can be either srcip or event_data.Workstation, depending on the data feed.

  • srcip_host — source host name
  • event_data.WorkstationName — workstation associated with the alerting srcip (when applicable)
  • event_id — Windows event ID corresponding to the login failures
  • login_type — type of login protocol; the available values vary by event_id
  • actual — actual number of failed logins with unknown user names in a 5-minute period
  • typical — typical number of failed logins with unknown user names in a 5-minute period
  • password_spray_user_summary — list of up to 100 unknown user names associated with the failed logins (the first three are shown in the alert description)

Use Case with Data Points

If a potential password spraying attack is observed, an alert is triggered. The Interflow includes a source (srcip or event_data.Workstation), timestamp, the type of login (login_type), the number of failed logins (actual), the usual number of failed logins (typical), and a sampling of the user names used in the attack (password_spray_user_summary).

...

Stellar Cyber reports both internal and external versions of some alerts, with different analysis and recommended actions for each. Similarly, IDS signatures report the direction of data flow as inbound or outbound. Use the following as a guide for these concepts:

  • Addresses with a srcip_type or dstip_type of private are identified as internal. All other values are identified as external (when applicable; not all alerts have unique analytics for internal/external).
  • Communications between hosts where srcip_type and dstip_type are both private are considered internal communications.
  • When an anomaly is observed on an internal communication, the attack is considered to be internal.
  • Stellar Cyber always sets the srcip in the Interflow record as the initiating IP address of an event. Note that IDS signatures, which are reported with relevant alerts, instead list addresses based on the direction of data flow, not the initiating address. So an INBOUND data flow may show the dstip as the source address and the srcip as the destination address, even though the srcip was the initiator of the request. Use INBOUND and OUTBOUND information in the signature to understand the direction of data flow, together with Stellar Cyber’s Interflow record of srcip and dstip to understand which address initiated the threat event.

Unsupervised

Y

Internal PII Leaked

Personally identifiable information (social security numbers or credit cards) has been observed in internal traffic in the clear. Check the source to see if it is compromised. If so, consider blocking it.

XDR Kill Chain

  • Kill Chain Stage: Exfiltration & Impact

  • Tactic: [Internal] Exfiltration (TA0010 )

  • Technique: Automated Exfiltration (T1020 )

  • Tags: [Internal; Network Traffic Analysis]

Event Name

The xdr_event.name for this alert type in the Interflow data is internal_pii_leak.

Severity

60

Key Fields and Relevant Data Points

  • srcip — source IP address of the PII leak 
  • dstip — destination IP address of the PII leak 
  • ids.signature — IDS signature of the exploit  
  • srcip_host — host name of corresponding source IP address
  • dstip_host — host name of corresponding destination IP address

Use Case with Data Points

If a personally identifiable information leak is detected by IDS, an alert is triggered. A sample Interflow includes the IDS signature (ids.signature), source IP address (srcip), destination IP address (dstip), source host (srcip_host), and destination host (dstip_host).

...

Stellar Cyber reports both internal and external versions of some alerts, with different analysis and recommended actions for each. Similarly, IDS signatures report the direction of data flow as inbound or outbound. Use the following as a guide for these concepts:

  • Addresses with a srcip_type or dstip_type of private are identified as internal. All other values are identified as external (when applicable; not all alerts have unique analytics for internal/external).
  • Communications between hosts where srcip_type and dstip_type are both private are considered internal communications.
  • When an anomaly is observed on an internal communication, the attack is considered to be internal.
  • Stellar Cyber always sets the srcip in the Interflow record as the initiating IP address of an event. Note that IDS signatures, which are reported with relevant alerts, instead list addresses based on the direction of data flow, not the initiating address. So an INBOUND data flow may show the dstip as the source address and the srcip as the destination address, even though the srcip was the initiator of the request. Use INBOUND and OUTBOUND information in the signature to understand the direction of data flow, together with Stellar Cyber’s Interflow record of srcip and dstip to understand which address initiated the threat event.

Analytics

N

Internal Plain Text Passwords Detected

A plain text password was observed in unencrypted traffic between internal systems. Check with the user.

XDR Kill Chain

  • Kill Chain Stage: Exploration

  • Tactic: [Internal] XDR NBA (XTA0002)

  • Technique: XDR Clear Password (XT2006)

  • Tags: [Internal; Network Traffic Analysis]

Event Name

The xdr_event.name for this alert type in the Interflow data is internal_clear_password.

Severity

30

Key Fields and Relevant Data Points

  • srcip — source IP address  
  • actual — actual number of connections with a plain text password in the period
  • srcip_host — host name of corresponding source IP address
  • dstip_host — host name of corresponding destination IP address
  • appid_name — application name

Use Case with Data Points

If there are plain text passwords in traffic records with a public source IP address (srcip) or destination IP address (dstip), an alert is triggered. A sample Interflow includes the source IP address (srcip), destination IP address (dstip), source host (srcip_host), destination host (dstip_host), and application (appid_name).

...

Stellar Cyber reports both internal and external versions of some alerts, with different analysis and recommended actions for each. Similarly, IDS signatures report the direction of data flow as inbound or outbound. Use the following as a guide for these concepts:

  • Addresses with a srcip_type or dstip_type of private are identified as internal. All other values are identified as external (when applicable; not all alerts have unique analytics for internal/external).
  • Communications between hosts where srcip_type and dstip_type are both private are considered internal communications.
  • When an anomaly is observed on an internal communication, the attack is considered to be internal.
  • Stellar Cyber always sets the srcip in the Interflow record as the initiating IP address of an event. Note that IDS signatures, which are reported with relevant alerts, instead list addresses based on the direction of data flow, not the initiating address. So an INBOUND data flow may show the dstip as the source address and the srcip as the destination address, even though the srcip was the initiator of the request. Use INBOUND and OUTBOUND information in the signature to understand the direction of data flow, together with Stellar Cyber’s Interflow record of srcip and dstip to understand which address initiated the threat event.

Analytics

N

Internal Protocol Account Login Failure Anomaly

An anomalously large number of login failures between internal IP addresses over SMB or FTP was observed. Check with the user.

XDR Kill Chain

  • Kill Chain Stage: Propagation

  • Tactic: [Internal] Credential Access (TA0006 )

  • Technique: Brute Force (T1110 )

  • Tags: [Internal; Network Traffic Analysis]

Event Name

The xdr_event.name for this alert type in the Interflow data is internal_protocol_account_login_failure.

Severity

60

Key Fields and Relevant Data Points

Use Case with Data Points

  • metadata.request.username — user name in the HTTP connection request  
  • event_summary.total_failed — number of failed logins in the period
  • event_summary.total_successful — number of successful logins in the period
  • event_summary.total_fail_ratio — percent of failed logins in the period, which is: event_summary.total_failed / (event_summary.total_failed + event_summary.total_successful)
  • weighted_anomaly_score — net score based on weighted rating of successful versus failed attempts (scanning, login, or other). Scores greater than upper threshold are potentially malicious and less than lower threshold are benign.
  • appid_name — application name
  • login_type — type of login
  • srcip_host — host name of corresponding source IP address
  • srcip_reputation — source reputation

For every user name (metadata.request.username) in the HTTP connections names (that do not begin with "Mozilla" or "Aella"), the number of failed and successful logins are calculated periodically. If the number of failed logins is much greater than successful logins, an alert is triggered. The Interflow includes the application name (appid_name), login type (login_type), source host (srcip_host), and source reputation (srcip_reputation).

...

Stellar Cyber reports both internal and external versions of some alerts, with different analysis and recommended actions for each. Similarly, IDS signatures report the direction of data flow as inbound or outbound. Use the following as a guide for these concepts:

  • Addresses with a srcip_type or dstip_type of private are identified as internal. All other values are identified as external (when applicable; not all alerts have unique analytics for internal/external).
  • Communications between hosts where srcip_type and dstip_type are both private are considered internal communications.
  • When an anomaly is observed on an internal communication, the attack is considered to be internal.
  • Stellar Cyber always sets the srcip in the Interflow record as the initiating IP address of an event. Note that IDS signatures, which are reported with relevant alerts, instead list addresses based on the direction of data flow, not the initiating address. So an INBOUND data flow may show the dstip as the source address and the srcip as the destination address, even though the srcip was the initiator of the request. Use INBOUND and OUTBOUND information in the signature to understand the direction of data flow, together with Stellar Cyber’s Interflow record of srcip and dstip to understand which address initiated the threat event.

Unsupervised

N

Internal PUA

Unwanted applications or malware that bombards the user with advertisements in internal traffic has been observed. Check with the user.

XDR Kill Chain

  • Kill Chain Stage: Propagation

  • Tactic: [Internal] XDR Malware (XTA0006)

  • Technique: XDR PUA (XT6002)

  • Tags: [Internal; Malware]

Event Name

The xdr_event.name for this alert type in the Interflow data is internal_pua.

Severity

60

Key Fields and Relevant Data Points

  • ids.signature — IDS signature  
  • maltrace-cloud.data.malicious_activity — malicious activity  
  • actual — number of records for one IDS signature or malicious activity in the period
  • lateral — boolean, indicating whether this activity is lateral (from private to private)
  • srcip_host — source host name
  • srcip_geo.countryName — source country
  • dstip_host — destination host name
  • dstip_geo.countryName — destination country
  • file_name — name of the file that carries the PUA
  • event_source — source of the event, either ids or sandbox

Use Case with Data Points

If ML-IDS or sandbox indicates potentially unwanted applications (PUA) in internal traffic, an alert is triggered. A sample Interflow includes malicious activity for sandbox (maltrace-cloud.data.malicious_activity), IDS signature for ML-IDS (ids.signature), event source (event_source), source host (srcip_host), source country (srcip_geo.countryName), destination host (dstip_host), destination country (dstip_geo.countryName), and the name of the file that carries the PUA (file_name) from the sandbox.

...

Stellar Cyber reports both internal and external versions of some alerts, with different analysis and recommended actions for each. Similarly, IDS signatures report the direction of data flow as inbound or outbound. Use the following as a guide for these concepts:

  • Addresses with a srcip_type or dstip_type of private are identified as internal. All other values are identified as external (when applicable; not all alerts have unique analytics for internal/external).
  • Communications between hosts where srcip_type and dstip_type are both private are considered internal communications.
  • When an anomaly is observed on an internal communication, the attack is considered to be internal.
  • Stellar Cyber always sets the srcip in the Interflow record as the initiating IP address of an event. Note that IDS signatures, which are reported with relevant alerts, instead list addresses based on the direction of data flow, not the initiating address. So an INBOUND data flow may show the dstip as the source address and the srcip as the destination address, even though the srcip was the initiator of the request. Use INBOUND and OUTBOUND information in the signature to understand the direction of data flow, together with Stellar Cyber’s Interflow record of srcip and dstip to understand which address initiated the threat event.

Analytics

N

Internal Ransomware

Malware that prevents you from accessing your system or files and demands ransom payment in order to regain access in internal traffic was observed. Check with the user.

XDR Kill Chain

  • Kill Chain Stage: Exfiltration & Impact

  • Tactic: [Internal] Impact (TA0040 )

  • Technique: Data Encrypted for Impact (T1486 )

  • Tags: [Internal; Malware; Ransomware]

Event Name

The xdr_event.name for this alert type in the Interflow data is internal_ransomware.

Severity

98

Key Fields and Relevant Data Points

  • ids.signature — IDS signature  
  • maltrace-cloud.data.malicious_activity — malicious activity  
  • actual — number of records for one IDS signature or malicious activity in the period
  • lateral — boolean, indicating whether this activity is lateral (from private to private)
  • srcip_host — source host name
  • srcip_geo.countryName — source country
  • dstip_host — destination host name
  • dstip_geo.countryName — destination country
  • file_name — name of the file that carries the ransomware
  • event_source — source of the event, either ids or sandbox

Use Case with Data Points

If ML-IDS or sandbox indicates ransomware in internal traffic, an alert is triggered. A sample Interflow includes malicious activity for sandbox (maltrace-cloud.data.malicious_activity), IDS signature for ML-IDS (ids.signature), event source (event_source), source host (srcip_host), source country (srcip_geo.countryName), destination host (dstip_host), destination country (dstip_geo.countryName), and the name of the file that carries the ransomware (file_name) from the sandbox.

...

Stellar Cyber reports both internal and external versions of some alerts, with different analysis and recommended actions for each. Similarly, IDS signatures report the direction of data flow as inbound or outbound. Use the following as a guide for these concepts:

  • Addresses with a srcip_type or dstip_type of private are identified as internal. All other values are identified as external (when applicable; not all alerts have unique analytics for internal/external).
  • Communications between hosts where srcip_type and dstip_type are both private are considered internal communications.
  • When an anomaly is observed on an internal communication, the attack is considered to be internal.
  • Stellar Cyber always sets the srcip in the Interflow record as the initiating IP address of an event. Note that IDS signatures, which are reported with relevant alerts, instead list addresses based on the direction of data flow, not the initiating address. So an INBOUND data flow may show the dstip as the source address and the srcip as the destination address, even though the srcip was the initiator of the request. Use INBOUND and OUTBOUND information in the signature to understand the direction of data flow, together with Stellar Cyber’s Interflow record of srcip and dstip to understand which address initiated the threat event.

Analytics

N

Internal RDP BlueKeep

The use of a scanner by zerosum0x0 that discovers targets vulnerable to BlueKeep (CVE-2019-0708) has been observed between internal hosts. Check the IP address and block if necessary.

XDR Kill Chain

  • Kill Chain Stage: Propagation

  • Tactic: [Internal] Privilege Escalation (TA0004 )

  • Technique: Exploitation for Privilege Escalation (T1068 )

  • Tags: [Internal; RDP]

Event Name

The xdr_event.name for this alert type in the Interflow data is internal_rdp_bluekeep.

Severity

90

Key Fields and Relevant Data Points

  • ids.signature — IDS signature 
  • srcip_host — source host name 
  • dstip_host — destination host name 

Use Case with Data Points

If the scanner by zerosum0x0 is used, an alert is triggered. A sample Interflow includes the IDS signature (ids.signature), source host (srcip_host), and destination host (dstip_host).

...

Stellar Cyber reports both internal and external versions of some alerts, with different analysis and recommended actions for each. Similarly, IDS signatures report the direction of data flow as inbound or outbound. Use the following as a guide for these concepts:

  • Addresses with a srcip_type or dstip_type of private are identified as internal. All other values are identified as external (when applicable; not all alerts have unique analytics for internal/external).
  • Communications between hosts where srcip_type and dstip_type are both private are considered internal communications.
  • When an anomaly is observed on an internal communication, the attack is considered to be internal.
  • Stellar Cyber always sets the srcip in the Interflow record as the initiating IP address of an event. Note that IDS signatures, which are reported with relevant alerts, instead list addresses based on the direction of data flow, not the initiating address. So an INBOUND data flow may show the dstip as the source address and the srcip as the destination address, even though the srcip was the initiator of the request. Use INBOUND and OUTBOUND information in the signature to understand the direction of data flow, together with Stellar Cyber’s Interflow record of srcip and dstip to understand which address initiated the threat event.

Analytics

N

Internal RDP Brute Force Attack

An anomalously large number of RDP connections from internal host(s) to an RDP server were observed. Check the source IP addresses to see if they are unknown or malicious, and monitor any successful RDP logins.

XDR Kill Chain

  • Kill Chain Stage:Propagation

  • Tactic: [Internal] Credential Access (TA0006 )

  • Technique: Brute Force (T1110 )

  • Tags: [Internal; Network Traffic Analysis]

Event Name

The xdr_event.name for this alert type in the Interflow data is internal_rdp_brute_force.

Severity

50

Key Fields and Relevant Data Points

  • dstip — IP address of the destination RDP server  
  • dstip_host — destination host name
  • actual — actual number of RDP connections to the destination IP address in the period
  • typical — typical number of RDP connections to the destination IP address in most time buckets
  • srcip — source IP address
  • srcip_host — source host name

Use Case with Data Points

RDP connection activity is monitored and the number of connections calculated periodically. If the number of connections from internal host(s) to an RDP server (actual) is much greater than normal (typical), an alert is triggered. A sample Interflow includes the destination IP address (dstip) and source IP address (srcip).

...

Stellar Cyber reports both internal and external versions of some alerts, with different analysis and recommended actions for each. Similarly, IDS signatures report the direction of data flow as inbound or outbound. Use the following as a guide for these concepts:

  • Addresses with a srcip_type or dstip_type of private are identified as internal. All other values are identified as external (when applicable; not all alerts have unique analytics for internal/external).
  • Communications between hosts where srcip_type and dstip_type are both private are considered internal communications.
  • When an anomaly is observed on an internal communication, the attack is considered to be internal.
  • Stellar Cyber always sets the srcip in the Interflow record as the initiating IP address of an event. Note that IDS signatures, which are reported with relevant alerts, instead list addresses based on the direction of data flow, not the initiating address. So an INBOUND data flow may show the dstip as the source address and the srcip as the destination address, even though the srcip was the initiator of the request. Use INBOUND and OUTBOUND information in the signature to understand the direction of data flow, together with Stellar Cyber’s Interflow record of srcip and dstip to understand which address initiated the threat event.

Unsupervised

Y

Internal RDP Suspicious Outbound

Non-standard tools from an internal host connecting to TCP port 3389 in the other internal host were observed. This could indicate lateral movement attempting to establish an RDP connection. Check the IP address and block if necessary.

XDR Kill Chain

  • Kill Chain Stage: Propagation

  • Tactic: [Internal] Lateral Movement (TA0008)

  • Technique: Remote Services (T1021)

  • Tags: [Internal; RDP]

Event Name

The xdr_event.name for this alert type in the Interflow data is internal_rdp_suspicious_outbound.

Severity

50

Key Fields and Relevant Data Points

  • srcip — source IP address of the host that connects to TCP port 3389 with a non-standard tool 
  • srcip_host — source host name
  • process_name — process name

Use Case with Data Points

Connections to TCP port 3389 are monitored, and if non-standard tools connect, an alert is triggered. A sample Interflow includes the source IP address (srcip) and the process name (process_name). The following are the standard tools:

  • mstsc.exe
  • RTSApp.exe
  • RTS2App.exe
  • RDCMan.exe
  • ws_TunnelService.exe
  • RSSensor.exe
  • RemoteDesktopManagerFree.exe
  • RemoteDesktopManager.exe
  • RemoteDesktopManager64.exe
  • mRemoteNG.exe
  • mRemote.exe
  • Terminals.exe
  • spiceworks-finder.exe
  • FSDiscovery.exe
  • FSAssessment.exe
  • MobaRTE.exe
  • chrome.exe
  • thor.exe
  • thor64.exe

...

Stellar Cyber reports both internal and external versions of some alerts, with different analysis and recommended actions for each. Similarly, IDS signatures report the direction of data flow as inbound or outbound. Use the following as a guide for these concepts:

  • Addresses with a srcip_type or dstip_type of private are identified as internal. All other values are identified as external (when applicable; not all alerts have unique analytics for internal/external).
  • Communications between hosts where srcip_type and dstip_type are both private are considered internal communications.
  • When an anomaly is observed on an internal communication, the attack is considered to be internal.
  • Stellar Cyber always sets the srcip in the Interflow record as the initiating IP address of an event. Note that IDS signatures, which are reported with relevant alerts, instead list addresses based on the direction of data flow, not the initiating address. So an INBOUND data flow may show the dstip as the source address and the srcip as the destination address, even though the srcip was the initiator of the request. Use INBOUND and OUTBOUND information in the signature to understand the direction of data flow, together with Stellar Cyber’s Interflow record of srcip and dstip to understand which address initiated the threat event.

Analytics

N

Internal Scanner Behavior Anomaly

An anomalously large amount of scanning behavior or a rarely seen scan behavior between internal hosts was observed. Cross-check with the IP/Port Scan Anomaly alert.

XDR Kill Chain

  • Kill Chain Stage: Exploration

  • Tactic: [Internal] Discovery (TA0007 )

  • Technique: Network Service Scanning (T1046 )

  • Tags: [Internal; Network Traffic Analysis]

Event Name

The xdr_event.name for this alert type in the Interflow data is internal_scan_anomalies.

Severity

40

Key Fields and Relevant Data Points

  • ids.signature — signature of the exploit  
  • actual — actual number of times this signature was found in the period, with critical IDS signatures counted as 2, high counted as 1, low counted as 0.5, and others counted as 1
  • typical — typical number of times this signature is seen in the period, with critical IDS signatures counted as 2, high counted as 1, low counted as 0.5, and others counted as 1
  • srcip_host — host name of corresponding source IP address
  • dstip_host — host name of corresponding destination IP address
  • appid_name — application name

Use Case with Data Points

The number of occurrences of each scanner, based on IDS signature (ids.signature) between internal hosts, is calculated periodically. If one scanner occurs (actual) much more often compared to its history (typical), an alert is triggered. A sample Interflow is presented with information such as the traffic application type (appid_name), source host (srcip_host), and destination host (dstip_host).

...

Stellar Cyber reports both internal and external versions of some alerts, with different analysis and recommended actions for each. Similarly, IDS signatures report the direction of data flow as inbound or outbound. Use the following as a guide for these concepts:

  • Addresses with a srcip_type or dstip_type of private are identified as internal. All other values are identified as external (when applicable; not all alerts have unique analytics for internal/external).
  • Communications between hosts where srcip_type and dstip_type are both private are considered internal communications.
  • When an anomaly is observed on an internal communication, the attack is considered to be internal.
  • Stellar Cyber always sets the srcip in the Interflow record as the initiating IP address of an event. Note that IDS signatures, which are reported with relevant alerts, instead list addresses based on the direction of data flow, not the initiating address. So an INBOUND data flow may show the dstip as the source address and the srcip as the destination address, even though the srcip was the initiator of the request. Use INBOUND and OUTBOUND information in the signature to understand the direction of data flow, together with Stellar Cyber’s Interflow record of srcip and dstip to understand which address initiated the threat event.

Unsupervised

Y

Internal SMB Read Anomaly

An internal IP address sent an anomalously large number of read requests to an internal SMB protocol based service(s). Investigate the files that this internal IP address tried to read. If suspicious, block the specific internal source IP address.

XDR Kill Chain

  • Kill Chain Stage: Propagation

  • Tactic: [Internal] Lateral Movement (TA0008 )

  • Technique: Exploitation of Remote Services (T1210 )

  • Tags: [Internal; Network Traffic Analysis]

Event Name

The xdr_event.name for this alert type in the Interflow data is internal_smb_read_anomaly.

Severity

20

Key Fields and Relevant Data Points

  • srcip — source IP address  
  • srcip_host — host name of corresponding source IP address
  • actual — actual number of SMB reads from the source IP address in the period
  • typical — typical number of SMB reads from other source IP addresses in the period
  • dstip_host — destination host name
  • smb_username — SMB user name

Use Case with Data Points

The number of SMB read requests for every internal source IP address (srcip) is calculated periodically. If a source IP address’s number of SMB reads (actual) is much larger than the typical number (typical) and that of other IP addresses in any period, an alert is triggered. The Interflow includes the SMB user (smb_username) and destination host (dstip_host).

...

Stellar Cyber reports both internal and external versions of some alerts, with different analysis and recommended actions for each. Similarly, IDS signatures report the direction of data flow as inbound or outbound. Use the following as a guide for these concepts:

  • Addresses with a srcip_type or dstip_type of private are identified as internal. All other values are identified as external (when applicable; not all alerts have unique analytics for internal/external).
  • Communications between hosts where srcip_type and dstip_type are both private are considered internal communications.
  • When an anomaly is observed on an internal communication, the attack is considered to be internal.
  • Stellar Cyber always sets the srcip in the Interflow record as the initiating IP address of an event. Note that IDS signatures, which are reported with relevant alerts, instead list addresses based on the direction of data flow, not the initiating address. So an INBOUND data flow may show the dstip as the source address and the srcip as the destination address, even though the srcip was the initiator of the request. Use INBOUND and OUTBOUND information in the signature to understand the direction of data flow, together with Stellar Cyber’s Interflow record of srcip and dstip to understand which address initiated the threat event.

Unsupervised

Y

Internal SMB Username Enumeration

At least 5 different users SMB login attempts and 1 denied attempt or at least 10 different users SMB login attempts, were observed from an internal IP address to other internal IP address(es). Check the source IP address. If malicious, consider blocking it.

XDR Kill Chain

  • Kill Chain Stage: Propagation

  • Tactic: [Internal] Credential Access (TA0006 )

  • Technique: Brute Force (T1110 )

  • Tags: [Internal; Network Traffic Analysis]

Event Name

The xdr_event.name for this alert type in the Interflow data is internal_smb_user_scan.

Severity

30

Key Fields and Relevant Data Points

  • srcip — source IP address  
  • srcip_host — host name of corresponding source IP address
  • dstip_host — host name of corresponding destination IP address
  • actual — actual unique SMB user count
  • typical — SMB user count threshold
  • smb_username_set — all SMB login user names

Use Case with Data Points

If an internal source IP address (srcip) has several SMB login attempts with (1) at least 5 unique user names and at least 1 denied attempt or (2) at least 10 unique user names, an alert is triggered. A sample Interflow includes the source IP address (srcip), source host (srcip_host), destination host (dstip_host), and all the user names (smb_username_set).

...

Stellar Cyber reports both internal and external versions of some alerts, with different analysis and recommended actions for each. Similarly, IDS signatures report the direction of data flow as inbound or outbound. Use the following as a guide for these concepts:

  • Addresses with a srcip_type or dstip_type of private are identified as internal. All other values are identified as external (when applicable; not all alerts have unique analytics for internal/external).
  • Communications between hosts where srcip_type and dstip_type are both private are considered internal communications.
  • When an anomaly is observed on an internal communication, the attack is considered to be internal.
  • Stellar Cyber always sets the srcip in the Interflow record as the initiating IP address of an event. Note that IDS signatures, which are reported with relevant alerts, instead list addresses based on the direction of data flow, not the initiating address. So an INBOUND data flow may show the dstip as the source address and the srcip as the destination address, even though the srcip was the initiator of the request. Use INBOUND and OUTBOUND information in the signature to understand the direction of data flow, together with Stellar Cyber’s Interflow record of srcip and dstip to understand which address initiated the threat event.

Analytics

N

Internal SMB Write Anomaly

An internal IP address sent an anomalously large number of SMB write requests to other internal IP address(es). Investigate the files that the IP address tried to write. If suspicious, block the source IP address.

XDR Kill Chain

  • Kill Chain Stage: Propagation

  • Tactic: [Internal] Lateral Movement (TA0008 )

  • Technique: Remote Services (T1021 )

  • Tags: [Internal; Network Traffic Analysis]

Event Name

The xdr_event.name for this alert type in the Interflow data is internal_smb_anomaly.

Severity

40

Key Fields and Relevant Data Points

  • srcip_host — source host name 
  • actual — actual number of SMB writes in the period
  • typical — typical number of SMB writes in the period
  • dstip_host — destination host name
  • smb_username — SMB user name

Use Case with Data Points

The number of SMB write requests to internal IP address(es) for every internal source IP address (srcip_host) is calculated periodically. If a source IP address’s number of SMB writes (actual) is much larger than the typical number (typical) and that of other IP addresses in any period, an alert is triggered. The Interflow includes the SMB user (smb_username) and destination host (dstip_host).

...

Stellar Cyber reports both internal and external versions of some alerts, with different analysis and recommended actions for each. Similarly, IDS signatures report the direction of data flow as inbound or outbound. Use the following as a guide for these concepts:

  • Addresses with a srcip_type or dstip_type of private are identified as internal. All other values are identified as external (when applicable; not all alerts have unique analytics for internal/external).
  • Communications between hosts where srcip_type and dstip_type are both private are considered internal communications.
  • When an anomaly is observed on an internal communication, the attack is considered to be internal.
  • Stellar Cyber always sets the srcip in the Interflow record as the initiating IP address of an event. Note that IDS signatures, which are reported with relevant alerts, instead list addresses based on the direction of data flow, not the initiating address. So an INBOUND data flow may show the dstip as the source address and the srcip as the destination address, even though the srcip was the initiator of the request. Use INBOUND and OUTBOUND information in the signature to understand the direction of data flow, together with Stellar Cyber’s Interflow record of srcip and dstip to understand which address initiated the threat event.

Unsupervised

Y

Internal Spyware

Malware that collects and shares information about a device without consent in internal traffic was observed. Check with the user.

XDR Kill Chain

  • Kill Chain Stage: Propagation

  • Tactic: [Internal] XDR Malware (XTA0006)

  • Technique: XDR Spyware (XT6003)

  • Tags: [Internal; Malware]

Event Name

The xdr_event.name for this alert type in the Interflow data is internal_spyware_activity.

Severity

60

Severity

60

Key Fields and Relevant Data Points

  • ids.signature — IDS signature  
  • maltrace-cloud.data.malicious_activity — malicious activity  
  • actual — number of records for one IDS signature or malicious activity in the period
  • lateral — boolean, indicating whether this activity is lateral (from private to private)
  • srcip_host — source host name
  • srcip_geo.countryName — source country
  • dstip_host — destination host name
  • dstip_geo.countryName — destination country
  • file_name — name of the file that carries the spyware
  • event_source — source of the event, either ids or sandbox

Use Case with Data Points

If ML-IDS or sandbox indicates spyware activity in internal traffic, an alert is triggered. A sample Interflow includes malicious activity for sandbox (maltrace-cloud.data.malicious_activity), IDS signature for ML-IDS (ids.signature), event source (event_source), source host (srcip_host), source country (srcip_geo.countryName), destination host (dstip_host), destination country (dstip_geo.countryName), and the name of the file that carries the spyware (file_name) from the sandbox.

...

Stellar Cyber reports both internal and external versions of some alerts, with different analysis and recommended actions for each. Similarly, IDS signatures report the direction of data flow as inbound or outbound. Use the following as a guide for these concepts:

  • Addresses with a srcip_type or dstip_type of private are identified as internal. All other values are identified as external (when applicable; not all alerts have unique analytics for internal/external).
  • Communications between hosts where srcip_type and dstip_type are both private are considered internal communications.
  • When an anomaly is observed on an internal communication, the attack is considered to be internal.
  • Stellar Cyber always sets the srcip in the Interflow record as the initiating IP address of an event. Note that IDS signatures, which are reported with relevant alerts, instead list addresses based on the direction of data flow, not the initiating address. So an INBOUND data flow may show the dstip as the source address and the srcip as the destination address, even though the srcip was the initiator of the request. Use INBOUND and OUTBOUND information in the signature to understand the direction of data flow, together with Stellar Cyber’s Interflow record of srcip and dstip to understand which address initiated the threat event.

Analytics

N

Internal SQL Anomaly

An internal IP address sent an anomalously large number of queries to an internal SQL server. Investigate the queries. If suspicious, block the source IP address.

XDR Kill Chain

  • Kill Chain Stage: Propagation

  • Tactic: [Internal] Lateral Movement (TA0008 )

  • Technique: Exploitation of Remote Services (T1210 )

  • Tags: [Internal; Network Traffic Analysis]

Event Name

The xdr_event.name for this alert type in the Interflow data is internal_mysql_anomaly.

Severity

30

Key Fields and Relevant Data Points

  • srcip — source IP address  
  • srcip_host — source host name
  • srcip_geo.countryName — source country
  • actual — actual number of SQL queries in the period
  • typical — typical number of SQL queries from the source IP address
  • dstip_host — destination host name

Use Case with Data Points

The number of SQL queries for every internal source IP address (srcip_host) is calculated periodically. If an internal source IP’s SQL query count (actual) is much larger than the typical count (typical) and that of other internal IP addresses in any period, an alert is triggered. The internal source IP’s country is (srcip_geo.countryName). The Interflow includes the internal destination host (dstip_host) the source IP visits.

...

Stellar Cyber reports both internal and external versions of some alerts, with different analysis and recommended actions for each. Similarly, IDS signatures report the direction of data flow as inbound or outbound. Use the following as a guide for these concepts:

  • Addresses with a srcip_type or dstip_type of private are identified as internal. All other values are identified as external (when applicable; not all alerts have unique analytics for internal/external).
  • Communications between hosts where srcip_type and dstip_type are both private are considered internal communications.
  • When an anomaly is observed on an internal communication, the attack is considered to be internal.
  • Stellar Cyber always sets the srcip in the Interflow record as the initiating IP address of an event. Note that IDS signatures, which are reported with relevant alerts, instead list addresses based on the direction of data flow, not the initiating address. So an INBOUND data flow may show the dstip as the source address and the srcip as the destination address, even though the srcip was the initiator of the request. Use INBOUND and OUTBOUND information in the signature to understand the direction of data flow, together with Stellar Cyber’s Interflow record of srcip and dstip to understand which address initiated the threat event.

Unsupervised

Y

Internal SQL Dumpfile Execution

The SQL dumpfile command between two internal IP addresses was observed. This command is commonly used to dump database content or query output to a file on disk. Check with the user.

XDR Kill Chain

  • Kill Chain Stage: Exploration

  • Tactic: [Internal] Collection (TA0009 )

  • Technique: Data Staged (T1074 )

  • Tags: [Internal; Network Traffic Analysis]

Event Name

The xdr_event.name for this alert type in the Interflow data is internal_sql_db_dump.

Severity

75

Key Fields and Relevant Data Points

  • srcip — source IP address  
  • actual — number of SQL dumpfile queries
  • srcip_host — source host name
  • source_geo.countryName — source country
  • dstip_host — destination host name

Use Case with Data Points

If any SQL dumpfile commands are detected between an internal source IP address (srcip) and an internal destination IP address (dstip), an alert is triggered. A sample Interflow includes the source IP address (srcip), source host (srcip_host), source country (srcip_geo.countryName), destination host (dstip_host), and the number of SQL dumpfile queries in the period (actual).

...

Stellar Cyber reports both internal and external versions of some alerts, with different analysis and recommended actions for each. Similarly, IDS signatures report the direction of data flow as inbound or outbound. Use the following as a guide for these concepts:

  • Addresses with a srcip_type or dstip_type of private are identified as internal. All other values are identified as external (when applicable; not all alerts have unique analytics for internal/external).
  • Communications between hosts where srcip_type and dstip_type are both private are considered internal communications.
  • When an anomaly is observed on an internal communication, the attack is considered to be internal.
  • Stellar Cyber always sets the srcip in the Interflow record as the initiating IP address of an event. Note that IDS signatures, which are reported with relevant alerts, instead list addresses based on the direction of data flow, not the initiating address. So an INBOUND data flow may show the dstip as the source address and the srcip as the destination address, even though the srcip was the initiator of the request. Use INBOUND and OUTBOUND information in the signature to understand the direction of data flow, together with Stellar Cyber’s Interflow record of srcip and dstip to understand which address initiated the threat event.

Analytics

N

Internal SQL Shell Command

Shell commands were observed over a SQL connection, which is a common way hackers try to gain shell access over vulnerable SQL applications. Check with the user.

XDR Kill Chain

  • Kill Chain Stage: Persistent Foothold

  • Tactic: [Internal] Execution (TA0002 )

  • Technique: Command and Scripting Interpreter (T1059 )

  • Tags: [Internal; Network Traffic Analysis]

Event Name

The xdr_event.name for this alert type in the Interflow data is internal_database_command.

Severity

70

Key Fields and Relevant Data Points

  • srcip — source IP address  
  • dstip — destination IP address  
  • srcip_host — source host name
  • srcip_reputation — source reputation
  • dstip_host — destination host name
  • dstip_reputation — destination reputation
  • metadata.request.query — SQL query command
  • actual — number of query records from one source to one destination in one period

Use Case with Data Points

For SQL query records, if special commands (such as select mylab_sys_exec) are found, an alert is triggered. A sample Interflow includes the source IP address (srcip), destination IP address (dstip), source host (srcip_host), source reputation (srcip_reputation), destination host (dstip_host), destination reputation (dstip_reputation), and SQL query records (metadata.request.query).

...

Stellar Cyber reports both internal and external versions of some alerts, with different analysis and recommended actions for each. Similarly, IDS signatures report the direction of data flow as inbound or outbound. Use the following as a guide for these concepts:

  • Addresses with a srcip_type or dstip_type of private are identified as internal. All other values are identified as external (when applicable; not all alerts have unique analytics for internal/external).
  • Communications between hosts where srcip_type and dstip_type are both private are considered internal communications.
  • When an anomaly is observed on an internal communication, the attack is considered to be internal.
  • Stellar Cyber always sets the srcip in the Interflow record as the initiating IP address of an event. Note that IDS signatures, which are reported with relevant alerts, instead list addresses based on the direction of data flow, not the initiating address. So an INBOUND data flow may show the dstip as the source address and the srcip as the destination address, even though the srcip was the initiator of the request. Use INBOUND and OUTBOUND information in the signature to understand the direction of data flow, together with Stellar Cyber’s Interflow record of srcip and dstip to understand which address initiated the threat event.

Analytics

N

Internal Suspected Malicious User Agent

An internal HTTP connection was made by a user agent that has been identified as potentially malicious. Investigate the connection's destination.

This alert type has two subtypes:

XDR Kill Chain

  • Kill Chain Stage: Exploration

  • Tactic: [Internal] XDR NBA (XTA0002)

  • Technique: XDR User Agent Anomaly (XT2012)

  • Tags: [Internal; Network Traffic Analysis]

Event Name

The xdr_event.name for this alert type in the Interflow data is internal_suspected_malicious_user_agent.

Severity

50

Key Fields and Relevant Data Points

  • metadata.request.user_agent — user agent in the HTTP connection request  
  • stellar.confidence — model's confidence in the prediction used to make the alert
  • srcip_host — host name of corresponding source IP address
  • dstip_host — host name of corresponding destination IP address
  • appid_name — application name

Use Case with Data Points

If a seen user agent is identified as suspicious, an alert is triggered. The alert will contain the suspicious user agent (metadata.request.user_agent), confidence (stellar.confidence), tenant (tenant_name), source IP (srcip), and destination IP (dstip) in the key fields. Additionally, the confidence level of the model is displayed in the alert description in a pop-up box.

Alert Subtype: Predicted Malicious Agent

The Predicted Malicious Agent alert subtype is the same as the Internal Suspected Malicious User Agent alert type above, with the following differences:

  • The stellar.anomaly_tag is predicted_internal.

  • The xdr_event.subtype.name is internal_suspected_malicious_user_agent.

  • It is triggered by a machine learning classifier.

Alert Subtype: Known Malicious Agent Match

The Known Malicious Agent Match alert subtype is the same as the Internal Suspected Malicious User Agent alert type above, with the following differences:

  • The stellar.anomaly_tag is known_internal.

  • The xdr_event.subtype.name is internal_suspected_malicious_user_agent_known_malicious.

  • It is triggered by known threats.

...

Stellar Cyber reports both internal and external versions of some alerts, with different analysis and recommended actions for each. Similarly, IDS signatures report the direction of data flow as inbound or outbound. Use the following as a guide for these concepts:

  • Addresses with a srcip_type or dstip_type of private are identified as internal. All other values are identified as external (when applicable; not all alerts have unique analytics for internal/external).
  • Communications between hosts where srcip_type and dstip_type are both private are considered internal communications.
  • When an anomaly is observed on an internal communication, the attack is considered to be internal.
  • Stellar Cyber always sets the srcip in the Interflow record as the initiating IP address of an event. Note that IDS signatures, which are reported with relevant alerts, instead list addresses based on the direction of data flow, not the initiating address. So an INBOUND data flow may show the dstip as the source address and the srcip as the destination address, even though the srcip was the initiator of the request. Use INBOUND and OUTBOUND information in the signature to understand the direction of data flow, together with Stellar Cyber’s Interflow record of srcip and dstip to understand which address initiated the threat event.

Supervised

N

Internal SYN Flood Attacker

An internal attacker sends a large amount of SYN requests to internal target system(s) in an attempt to consume enough server resources to make the system unresponsive to legitimate traffic.

XDR Kill Chain

  • Kill Chain Stage: Exfiltration & Impact

  • Tactic: [Internal] Impact (TA0040 )

  • Technique: Endpoint Denial of Service (T1499 )

  • Tags: [Internal; Network Traffic Analysis]

Event Name

The xdr_event.name for this alert type in the Interflow data is internal_syn_flood_attacker.

Severity

25

Key Fields and Relevant Data Points

  • srcip — source IP address of the SYN flood  
  • srcip_host — source host name
  • dstip — target IP address of the SYN flood  
  • dstip_host — destination host name
  • dstport — port on target host that received the SYN flood
  • syn_flood_events — number of SYN packets during the period

Use Case with Data Points

If an internal host (srcip) sends too many SYN packets (syn_flood_events) to internal target(s) (dstip) in a five-minute time window, an alert is triggered. The Interflow includes the IP address of the source host (srcip), the IP address of the target host (dstip), the port of the target host (dstport), and how many SYN packets were observed (actual).

...

Stellar Cyber reports both internal and external versions of some alerts, with different analysis and recommended actions for each. Similarly, IDS signatures report the direction of data flow as inbound or outbound. Use the following as a guide for these concepts:

  • Addresses with a srcip_type or dstip_type of private are identified as internal. All other values are identified as external (when applicable; not all alerts have unique analytics for internal/external).
  • Communications between hosts where srcip_type and dstip_type are both private are considered internal communications.
  • When an anomaly is observed on an internal communication, the attack is considered to be internal.
  • Stellar Cyber always sets the srcip in the Interflow record as the initiating IP address of an event. Note that IDS signatures, which are reported with relevant alerts, instead list addresses based on the direction of data flow, not the initiating address. So an INBOUND data flow may show the dstip as the source address and the srcip as the destination address, even though the srcip was the initiator of the request. Use INBOUND and OUTBOUND information in the signature to understand the direction of data flow, together with Stellar Cyber’s Interflow record of srcip and dstip to understand which address initiated the threat event.

Analytics

N

Internal SYN Flood Victim

A large amount of SYN requests to an internal target were observed, which can indicate an attempt to consume server resources and make the target unresponsive. Check to see if the host is malicious or compromised. If so, consider blocking the source host.

XDR Kill Chain

  • Kill Chain Stage: Exfiltration & Impact

  • Tactic: [Internal] Impact (TA0040 )

  • Technique: Endpoint Denial of Service (T1499 )

  • Tags: [Internal; Network Traffic Analysis]

Event Name

The xdr_event.name for this alert type in the Interflow data is internal_syn_flood.

Severity

25

Key Fields and Relevant Data Points

  • srcip — source IP address for the SYN flood
  • srcip_host — source host name
  • dstip — target IP address of the SYN flood  
  • dstip_host — destination host name
  • dstport — port on target host that received the SYN flood
  • syn_flood_events — number of SYN packets during the period

Use Case with Data Points

If an internal host (srcip) sends too many SYN packets (syn_flood_events) to internal target(s) (dstip) in a five-minute time window, an alert is triggered. The Interflow includes the IP address of the source host (srcip), the IP address of the target host (dstip), the port of the target host (dstport), and how many SYN packets were observed (actual).

...

Stellar Cyber reports both internal and external versions of some alerts, with different analysis and recommended actions for each. Similarly, IDS signatures report the direction of data flow as inbound or outbound. Use the following as a guide for these concepts:

  • Addresses with a srcip_type or dstip_type of private are identified as internal. All other values are identified as external (when applicable; not all alerts have unique analytics for internal/external).
  • Communications between hosts where srcip_type and dstip_type are both private are considered internal communications.
  • When an anomaly is observed on an internal communication, the attack is considered to be internal.
  • Stellar Cyber always sets the srcip in the Interflow record as the initiating IP address of an event. Note that IDS signatures, which are reported with relevant alerts, instead list addresses based on the direction of data flow, not the initiating address. So an INBOUND data flow may show the dstip as the source address and the srcip as the destination address, even though the srcip was the initiator of the request. Use INBOUND and OUTBOUND information in the signature to understand the direction of data flow, together with Stellar Cyber’s Interflow record of srcip and dstip to understand which address initiated the threat event.

Analytics

N

Internal Trojan

Malware that disguises itself as legitimate software in order to gain access to a system or files in internal traffic has been observed. Check with the user.

XDR Kill Chain

  • Kill Chain Stage: Propagation

  • Tactic: [Internal] XDR Malware (XTA0006)

  • Technique: XDR Trojan (XT6004)

  • Tags: [Internal; Malware]

Event Name

The xdr_event.name for this alert type in the Interflow data is internal_trojan_activity.

Severity

70

Key Fields and Relevant Data Points

  • ids.signature — IDS signature  
  • maltrace-cloud.data.malicious_activity — malicious activity  
  • actual — number of records for one IDS signature or malicious activity in the period
  • lateral — boolean, indicating whether this activity is lateral (from private to private)
  • srcip_host — source host name
  • srcip_geo.countryName — source country
  • dstip_host — destination host name
  • dstip_geo.countryName — destination country
  • file_name — name of the file that carries the trojan
  • event_source — source of the event, either ids or sandbox

Use Case with Data Points

If ML-IDS or sandbox indicates trojan activity in internal traffic, an alert is triggered. A sample Interflow includes malicious activity for sandbox (maltrace-cloud.data.malicious_activity), IDS signature for ML-IDS (ids.signature), event source (event_source), source host (srcip_host), source country (srcip_geo.countryName), destination host (dstip_host), destination country (dstip_geo.countryName), and the name of the file that carries the trojan (file_name) from the sandbox.

...

Stellar Cyber reports both internal and external versions of some alerts, with different analysis and recommended actions for each. Similarly, IDS signatures report the direction of data flow as inbound or outbound. Use the following as a guide for these concepts:

  • Addresses with a srcip_type or dstip_type of private are identified as internal. All other values are identified as external (when applicable; not all alerts have unique analytics for internal/external).
  • Communications between hosts where srcip_type and dstip_type are both private are considered internal communications.
  • When an anomaly is observed on an internal communication, the attack is considered to be internal.
  • Stellar Cyber always sets the srcip in the Interflow record as the initiating IP address of an event. Note that IDS signatures, which are reported with relevant alerts, instead list addresses based on the direction of data flow, not the initiating address. So an INBOUND data flow may show the dstip as the source address and the srcip as the destination address, even though the srcip was the initiator of the request. Use INBOUND and OUTBOUND information in the signature to understand the direction of data flow, together with Stellar Cyber’s Interflow record of srcip and dstip to understand which address initiated the threat event.

Analytics

N

Internal URL Reconnaissance Anomaly

An anomalous number of HTTP 4xx errors from an internal IP address to other internal IP addresses were observed. This can indicate an attacker scanning for pages to exploit. Check with the user.

XDR Kill Chain

  • Kill Chain Stage: Exploration

  • Tactic: [Internal] Discovery (TA0007 )

  • Technique: Network Service Scanning (T1046 )

  • Tags: [Internal; Network Traffic Analysis]

Event Name

The xdr_event.name for this alert type in the Interflow data is internal_url_scan.

Severity

50

Key Fields and Relevant Data Points

  • srcip — source IP address  
  • event_summary.total_failed — number of unique URLs with HTTP error status response in the period
  • event_summary.total_successful — number of unique URLs with HTTP success status response in the period
  • event_summary.total_fail_ratio — percent of unique URLs with HTTP error status response in the period, which is: event_summary.total_failed / (event_summary.total_failed + event_summary.total_successful)
  • weighted_anomaly_score — net score based on weighted rating of successful versus failed attempts (scanning, login, or other). Scores greater than upper threshold are potentially malicious and less than lower threshold are benign.
  • srcip_host — host name of corresponding source IP address
  • dstip_host — host name of corresponding destination IP address
  • srcip_geo.countryName — source country name

Use Case with Data Points

For each internal source IP address (srcip), the number of unique URLs that responded with failure HTTP status and the number of unique URLs that responded with success HTTP status are calculated periodically. If the fail metric is significantly larger than the success metric, an alert is triggered. A sample Interflow includes the source host (srcip_host), destination host (dstip_host), and source country (srcip_geo.countryName).

...

Stellar Cyber reports both internal and external versions of some alerts, with different analysis and recommended actions for each. Similarly, IDS signatures report the direction of data flow as inbound or outbound. Use the following as a guide for these concepts:

  • Addresses with a srcip_type or dstip_type of private are identified as internal. All other values are identified as external (when applicable; not all alerts have unique analytics for internal/external).
  • Communications between hosts where srcip_type and dstip_type are both private are considered internal communications.
  • When an anomaly is observed on an internal communication, the attack is considered to be internal.
  • Stellar Cyber always sets the srcip in the Interflow record as the initiating IP address of an event. Note that IDS signatures, which are reported with relevant alerts, instead list addresses based on the direction of data flow, not the initiating address. So an INBOUND data flow may show the dstip as the source address and the srcip as the destination address, even though the srcip was the initiator of the request. Use INBOUND and OUTBOUND information in the signature to understand the direction of data flow, together with Stellar Cyber’s Interflow record of srcip and dstip to understand which address initiated the threat event.

Unsupervised

N

Internal User Agent Anomaly

An internal HTTP connection was made by an internal user agent that has never been seen before (or been seen very rarely). Investigate the connection destination.

XDR Kill Chain

  • Kill Chain Stage: Exploration

  • Tactic: [Internal] XDR NBA (XTA0002)

  • Technique: XDR User Agent Anomaly (XT2012)

  • Tags: [Internal; Network Traffic Analysis]

Event Name

The xdr_event.name for this alert type in the Interflow data is internal_user_agent_anomaly.

Severity

35

Key Fields and Relevant Data Points

  • metadata.request.user_agent — user agent in the HTTP connection request  
  • days_silent — number of days since this user agent was last seen
  • srcip_host — host name of corresponding source IP address
  • dstip_host — host name of corresponding destination IP address
  • appid_name — application name

Use Case with Data Points

All user agents (metadata.request.user_agent) with internal HTTP connections having names that do not begin with "Mozilla" or "Aella" are examined. An alert is triggered if any of those agents have not been observed by Stellar Cyber before or have been silent for many days (days_silent). The Interflow includes all information from the suspicious HTTP connection, such as the application (appid_name), the source host name (srcip_host), and the destination host name (dstip_host).

...

Stellar Cyber reports both internal and external versions of some alerts, with different analysis and recommended actions for each. Similarly, IDS signatures report the direction of data flow as inbound or outbound. Use the following as a guide for these concepts:

  • Addresses with a srcip_type or dstip_type of private are identified as internal. All other values are identified as external (when applicable; not all alerts have unique analytics for internal/external).
  • Communications between hosts where srcip_type and dstip_type are both private are considered internal communications.
  • When an anomaly is observed on an internal communication, the attack is considered to be internal.
  • Stellar Cyber always sets the srcip in the Interflow record as the initiating IP address of an event. Note that IDS signatures, which are reported with relevant alerts, instead list addresses based on the direction of data flow, not the initiating address. So an INBOUND data flow may show the dstip as the source address and the srcip as the destination address, even though the srcip was the initiator of the request. Use INBOUND and OUTBOUND information in the signature to understand the direction of data flow, together with Stellar Cyber’s Interflow record of srcip and dstip to understand which address initiated the threat event.

Unsupervised

Y

Internal User Application Usage Anomaly

An internal user who usually runs a few applications with internal service IP addresses suddenly runs a new application. Investigate the application to see if it is benign. Check with the user to see if this was expected.

XDR Kill Chain

  • Kill Chain Stage: Propagation

  • Tactic: [Internal] XDR UBA (XTA0004)

  • Technique: XDR App Anomaly (XT2003)

  • Tags: [Internal; User Behavior Analytics]

Event Name

The xdr_event.name for this alert type in the Interflow data is internal_user_uncommon_app.

Severity

10

Key Fields and Relevant Data Points

  • srcip_usersid — source user ID  
  • appid_name — application name
  • srcip_host — host name of corresponding source IP address
  • dstip_host — host name of corresponding destination IP address
  • appid_family — application family
  • srcip_username — source user name
  • stability — score measuring the time since the last new application was used
  • days_stable — time since the last new application was used
  • diversity — score measuring the number of applications that the user used
  • child_count — number of applications that the user used

Use Case with Data Points

An alert is triggered under the following conditions:

  • a user (srcip_usersid, srcip_username) with a small number of applications (diversity, child_count) who has not used a new application for a long period of time (stability, days_stable), and then

  • a new application (appid_name) belonging to an application family (appid_family) appears on a host (scrip_host) with this user, and

  • that host connects to another host (scrip_host)

...

Stellar Cyber reports both internal and external versions of some alerts, with different analysis and recommended actions for each. Similarly, IDS signatures report the direction of data flow as inbound or outbound. Use the following as a guide for these concepts:

  • Addresses with a srcip_type or dstip_type of private are identified as internal. All other values are identified as external (when applicable; not all alerts have unique analytics for internal/external).
  • Communications between hosts where srcip_type and dstip_type are both private are considered internal communications.
  • When an anomaly is observed on an internal communication, the attack is considered to be internal.
  • Stellar Cyber always sets the srcip in the Interflow record as the initiating IP address of an event. Note that IDS signatures, which are reported with relevant alerts, instead list addresses based on the direction of data flow, not the initiating address. So an INBOUND data flow may show the dstip as the source address and the srcip as the destination address, even though the srcip was the initiator of the request. Use INBOUND and OUTBOUND information in the signature to understand the direction of data flow, together with Stellar Cyber’s Interflow record of srcip and dstip to understand which address initiated the threat event.

Unsupervised

Y

Internal User Data Volume Anomaly

A user had an anomalously large volume of internal traffic compared to its typical volume or that of its peers. Investigate the user to determine if this is expected.

Firewall and non-firewall data do not contribute to the same alert, so this alert will have either entirely firewall data or no firewall data.

XDR Kill Chain

  • Kill Chain Stage: Propagation

  • Tactic: [Internal] XDR UBA (XTA0004)

  • Technique: XDR Bytes Anomaly (XT3001)

  • Tags: [Internal; User Behavior Analytics]

Event Name

The xdr_event.name for this alert type in the Interflow data is internal_user_bytes_sum.

Severity

20

Key Fields and Relevant Data Points

  • srcip_usersid — source user ID  
  • actual — actual traffic volume in the period
  • typical — typical traffic volume from the user
  • srcip_host — host name of corresponding source IP address
  • srcip_username — source user name
  • dstip_host — host name of corresponding destination IP address
  • dstip_reputation — destination reputation
  • dstip_geo.countryName — destination country
  • appid_name — application name

Use Case with Data Points

The total internal traffic volume of each user identified by user ID (scrip_usersid) is calculated periodically. If the volume in one period (actual) is much larger than its normal volume (typical), an alert is triggered.

The Interflow includes the source IP address (srcip_host), destination IP address (dstip_host), destination reputation (dstip_reputation), destination country (dstip_geo.countryName), and application of the traffic (appid_name).

...

Stellar Cyber reports both internal and external versions of some alerts, with different analysis and recommended actions for each. Similarly, IDS signatures report the direction of data flow as inbound or outbound. Use the following as a guide for these concepts:

  • Addresses with a srcip_type or dstip_type of private are identified as internal. All other values are identified as external (when applicable; not all alerts have unique analytics for internal/external).
  • Communications between hosts where srcip_type and dstip_type are both private are considered internal communications.
  • When an anomaly is observed on an internal communication, the attack is considered to be internal.
  • Stellar Cyber always sets the srcip in the Interflow record as the initiating IP address of an event. Note that IDS signatures, which are reported with relevant alerts, instead list addresses based on the direction of data flow, not the initiating address. So an INBOUND data flow may show the dstip as the source address and the srcip as the destination address, even though the srcip was the initiator of the request. Use INBOUND and OUTBOUND information in the signature to understand the direction of data flow, together with Stellar Cyber’s Interflow record of srcip and dstip to understand which address initiated the threat event.

Unsupervised

Y

Internal User Login Failure Anomaly

An anomalous number of login failures between internal IP addresses was observed for one of the following applications: SSH, SMTP, FTP, RDP, SMB, databases, Active Directory, Office 365, Okta, AWS CloudTrail, Google Workspace, Salesforce, or Microsoft Entra ID (formerly Azure Active Directory). Check with the user.

This alert type has a relatively long detection delay of up to 40 minutes because it waits for login events from high latency data sources and is sensitive to the event order of user logins.

XDR Kill Chain

  • Kill Chain Stage: Propagation

  • Tactic: [Internal] Credential Access (TA0006 )

  • Technique: Brute Force (T1110 )

  • Tags: [Internal]

Event Name

The xdr_event.name for this alert type in the Interflow data is internal_user_login_fail.

Severity

60

Key Fields and Relevant Data Points

  • srcip — source IP address  
  • service_id — source domain, workstation, organization, or service 
  • dstip — destination IP address  
  • dstip_host — destination host name
  • event_summary.total_failed — number of failed logins in the period
  • event_summary.total_successful — number of successful logins in the period
  • event_summary.total_fail_ratio — percent of failed logins in the period, which is: event_summary.total_failed / (event_summary.total_failed + event_summary.total_successful)
  • weighted_anomaly_score — net score based on weighted rating of successful versus failed attempts (scanning, login, or other). Scores greater than upper threshold are potentially malicious and less than lower threshold are benign.
  • login_type — type of login, such as ssh_traffic, okta_log, or aws_cloudtrail
  • srcip_host — source host name
  • srcip_reputation — source reputation

Use Case with Data Points

Login failures and successes between internal IP addresses are calculated periodically for every source (srcip) and destination (dstip) IP address. If the number of failures is significantly larger than the number of successes, an alert is triggered. The Interflow includes the login type (login_type), source host (srcip_host), and source reputation (srcip_reputation).

...

Stellar Cyber reports both internal and external versions of some alerts, with different analysis and recommended actions for each. Similarly, IDS signatures report the direction of data flow as inbound or outbound. Use the following as a guide for these concepts:

  • Addresses with a srcip_type or dstip_type of private are identified as internal. All other values are identified as external (when applicable; not all alerts have unique analytics for internal/external).
  • Communications between hosts where srcip_type and dstip_type are both private are considered internal communications.
  • When an anomaly is observed on an internal communication, the attack is considered to be internal.
  • Stellar Cyber always sets the srcip in the Interflow record as the initiating IP address of an event. Note that IDS signatures, which are reported with relevant alerts, instead list addresses based on the direction of data flow, not the initiating address. So an INBOUND data flow may show the dstip as the source address and the srcip as the destination address, even though the srcip was the initiator of the request. Use INBOUND and OUTBOUND information in the signature to understand the direction of data flow, together with Stellar Cyber’s Interflow record of srcip and dstip to understand which address initiated the threat event.

Unsupervised

N

Login Time Anomaly

A user logged in at an abnormal time. Check with the user.

This alert type has a relatively long detection delay of up to 40 minutes because it waits for login events from high latency data sources and is sensitive to the event order of user logins.

This alert type reads the System Timezone in Global Settings and puts the timezone into the alert descriptions. In Global Settings, set your timezone relative to UTC.

When a Login Time Anomaly occurs, the timezone is bound to the alert description with the following priorities:

  • The timezone inferred from engid_gateway takes precedence over the DP timezone, but only when it is present. If engid_gateway is present, the description will use the timezone where the login actually happened.

  • If engid_gateway is not present, the DP timezone setting is used.

XDR Kill Chain

  • Kill Chain Stage: Initial Attempts

  • Tactic: [External] XDR UBA (XTA0004)

  • Technique: XDR Time Anomaly (XT4005)

  • Tags: [External; User Behavior Analytics]

Event Name

The xdr_event.name for this alert type in the Interflow data is user_login_time.

Severity

40

Key Fields and Relevant Data Points

  • srcip_usersid — key ID of the source user 

    or

  • event_data.TargetUserName — name of the user (Windows event)  

  • The key field for this alert type can be either srcip_usersid or event_data.TargetUserName, depending on the data feed.

  • srcip_username — source user name
  • srcip_host — host name of corresponding source IP address
  • srcip_geo.countryName — source country
  • actual_range — actual login time range
  • typical_range — typical login time range

Use Case with Data Points

Every user's (srcip_usersid) login time (actual) is compared to the typical login times (typical_range). If it is outside the range, an alert is triggered. The Interflow includes information such as the source user name (srcip_username), source host name (srcip_host), and source country (srcip_geo.countryName), as well as the destination host (dstip_host).

Unsupervised

Y

Long App Session Anomaly

An application had an anomalously long session compared to its typical session length or that of its peers. Investigate the application to see if this session was expected.

XDR Kill Chain

  • Kill Chain Stage: Initial Attempts

  • Tactic: [External] XDR NBA (XTA0002)

  • Technique: XDR Session Anomaly (XT2005)

  • Tags: [External; Network Traffic Analysis]

Event Name

The xdr_event.name for this alert type in the Interflow data is long_session_anomaly.

Severity

30

Key Fields and Relevant Data Points

  • appid_name — application name  
  • actual — actual maximum session length in the period
  • typical — typical session length from the application’s own history
  • srcip_host — host name of corresponding source IP address
  • dstip_host — host name of corresponding destination IP address

Use Case with Data Points

Every application's (appid_name) maximum session duration is calculated periodically. If an application’s maximum duration (actual) is much larger than its normal value (typical) or the typical value of other applications, an alert is triggered. The Interflow includes the source host (srcip_host) and destination host (dstip_host).

Unsupervised

Y

Malicious Site Access

A host accessed a URL with a reputation for potentially hosting malware. Check the URL and, if malicious, consider blocking it. Check the host for compromise.

XDR Kill Chain

  • Kill Chain Stage: Initial Attempts

  • Tactic: [External] XDR NBA (XTA0002)

  • Technique: XDR Bad Reputation (XT2010)

  • Tags: [External; Network Traffic Analysis]

Event Name

The xdr_event.name for this alert type in the Interflow data is mal_access.

Severity

60

Key Fields and Relevant Data Points

  • srcip — source IP address of the host that initiated the site access 
  • srcip_host — source host name
  • url — URL that was accessed 
  • url_reputation — reputation of the accessed URL

Use Case with Data Points

When a host (srcip) accesses a URL with a reputation (srcip_reputation) as potential malware hosting (MalAccess), an alert is triggered. The Interflow includes the source host IP address (srcip), the URL accessed (url), and the reputation of the URL (url_reputation).

Analytics

N

Malware on Disk

Malicious software or a potentially unwanted application was found on a device and reported as not cleaned. Check with the user.

XDR Kill Chain

  • Kill Chain Stage: Propagation

  • Tactic: [Internal] XDR Malware (XTA0006)

  • Technique: XDR Miscellaneous Malware (XT6001)

  • Tags: [Internal; Malware]

Event Name

The xdr_event.name for this alert type in the Interflow data is malware_on_disk.

Severity

80

Key Fields and Relevant Data Points

  • hostip — IP address of the host 
  • file_path — file path 
  • computer_name — computer name
  • malware_engine — malware engine, can be Sophos or Windows Defender
  • group — type of malware
  • type — status of malware

Use Case with Data Points

If either of the following occurs, an alert is triggered:

  • Sophos engine indicates there is uncleaned malware
  • Windows Defender indicates a failure or error when taking actions to protect the system

A sample Interflow includes the computer name (computer_name), malware engine (malware_engine), host IP address (hostip), path to the file (file_path), type of malware (group, for Sophos), and status of the malware (type, for Sophos).

Analytics

N

Microsoft Entra Application Configuration Changes

The Microsoft Entra Application Configuration Changes rules are used to identify suspicious Microsoft Entra application configuration changes. Any one or more of these will trigger the Microsoft Entra Application Configuration Changes alert type.

Event Name

The xdr_event.name for this alert type in the Interflow data is azure_application_configuration_changes.

Key Fields and Relevant Data Points

  • initiatedBy.user.id — user ID who initiated the activity 
  • initiatedBy.app.servicePrincipalId — application and Service Principal ID that initiated the activity 
  • user.name — user name
  • activityDisplayName — activity display name
  • category — activity category
  • result — result of the activity
  • resultReason — result reason of the activity
  • stellar.rule_id — Stellar Cyber rule ID

Link to Rule-Based Alert Types

Rules Contributing to Microsoft Entra Application Configuration Changes Alert Type

Analytics

N

Microsoft Entra Application Permission Changes

The Microsoft Entra Application Permission Changes rules are used to identify suspicious Microsoft Entra application permission changes. Any one or more of these will trigger the Microsoft Entra Application Permission Changes alert type.

Event Name

The xdr_event.name for this alert type in the Interflow data is azure_application_permission_changes.

Key Fields and Relevant Data Points

  • initiatedBy.user.id — user ID who initiated the activity 
  • initiatedBy.app.servicePrincipalId — application and Service Principal ID that initiated the activity 
  • user.name — user name
  • activityDisplayName — activity display name
  • category — activity category
  • result — result of the activity
  • resultReason — result reason of the activity
  • stellar.rule_id — Stellar Cyber rule ID

Link to Rule-Based Alert Types

Rules Contributing to Microsoft Entra Application Permission Changes Alert Type

Analytics

N

Microsoft Entra Bitlocker Key Retrieval

The Microsoft Entra Bitlocker Key Retrieval rules are used to identify suspicious Microsoft Entra bitlocker key retrieval activity. Any one or more of these will trigger the Microsoft Entra Bitlocker Key Retrieval alert type.

Event Name

The xdr_event.name for this alert type in the Interflow data is azure_bitlocker_key_retrieval.

Key Fields and Relevant Data Points

  • initiatedBy.user.id — user ID who initiated the activity 
  • initiatedBy.app.servicePrincipalId — application and Service Principal ID that initiated the activity 
  • user.name — user name
  • activityDisplayName — activity display name
  • category — activity category
  • result — result of the activity
  • resultReason — result reason of the activity
  • stellar.rule_id — Stellar Cyber rule ID

Link to Rule-Based Alert Types

Rules Contributing to Microsoft Entra Bitlocker Key Retrieval Alert Type

Analytics

N

Microsoft Entra Changes to Conditional Access Policy

The Microsoft Entra Changes to Conditional Access Policy rules are used to identify suspicious Microsoft Entra changes to conditional access policy. Any one or more of these will trigger the Microsoft Entra Changes to Conditional Access Policy alert type.

Event Name

The xdr_event.name for this alert type in the Interflow data is azure_suspicious_changes_to_conditional_access_policy.

Key Fields and Relevant Data Points

  • initiatedBy.user.id — user ID who initiated the activity 
  • initiatedBy.app.servicePrincipalId — application and Service Principal ID that initiated the activity 
  • user.name — user name
  • activityDisplayName — activity display name
  • category — activity category
  • result — result of the activity
  • resultReason — result reason of the activity
  • stellar.rule_id — Stellar Cyber rule ID

Link to Rule-Based Alert Types

Rules Contributing to Microsoft Entra Changes to Conditional Access Policy Alert Type

Analytics

N

Microsoft Entra Changes to Device Registration Policy

The Microsoft Entra Changes to Device Registration Policy rules are used to identify suspicious Microsoft Entra changes to device registration policy. Any one or more of these will trigger the Microsoft Entra Changes to Device Registration Policy alert type.

Event Name

The xdr_event.name for this alert type in the Interflow data is azure_changes_to_device_registration_policy.

Key Fields and Relevant Data Points

  • initiatedBy.user.id — user ID who initiated the activity 
  • initiatedBy.app.servicePrincipalId — application and Service Principal ID that initiated the activity 
  • user.name — user name
  • activityDisplayName — activity display name
  • category — activity category
  • result — result of the activity
  • resultReason — result reason of the activity
  • stellar.rule_id — Stellar Cyber rule ID

Link to Rule-Based Alert Types

Rules Contributing to Microsoft Entra Changes to Device Registration Policy Alert Type

Analytics

N

Microsoft Entra Changes to Privileged Account

The Microsoft Entra Changes to Privileged Account rules are used to identify suspicious Microsoft Entra changes to privileged account. Any one or more of these will trigger the Microsoft Entra Changes to Privileged Account alert type.

Event Name

The xdr_event.name for this alert type in the Interflow data is azure_changes_to_privileged_account.

Key Fields and Relevant Data Points

  • initiatedBy.user.id — user ID who initiated the activity 
  • initiatedBy.app.servicePrincipalId — application and Service Principal ID that initiated the activity 
  • user.name — user name
  • activityDisplayName — activity display name
  • category — activity category
  • result — result of the activity
  • resultReason — result reason of the activity
  • stellar.rule_id — Stellar Cyber rule ID

Link to Rule-Based Alert Types

Rules Contributing to Microsoft Entra Changes to Privileged Account Alert Type

Analytics

N

Microsoft Entra Changes to Privileged Role Assignment

The Microsoft Entra Changes to Privileged Role Assignment rules are used to identify suspicious Microsoft Entra changes to privileged role assignment. Any one or more of these will trigger the Microsoft Entra Changes to Privileged Role Assignment alert type.

Event Name

The xdr_event.name for this alert type in the Interflow data is azure_changes_to_privileged_role_assignment.

Key Fields and Relevant Data Points

  • initiatedBy.user.id — user ID who initiated the activity 
  • initiatedBy.app.servicePrincipalId — application and Service Principal ID that initiated the activity 
  • user.name — user name
  • activityDisplayName — activity display name
  • category — activity category
  • result — result of the activity
  • resultReason — result reason of the activity
  • stellar.rule_id — Stellar Cyber rule ID

Link to Rule-Based Alert Types

Rules Contributing to Microsoft Entra Changes to Privileged Role Assignment Alert Type

Analytics

N

Microsoft Entra Federation Modified

The Microsoft Entra Federation Modified rules are used to identify suspicious Microsoft Entra federation modified activity. Any one or more of these will trigger the Microsoft Entra Federation Modified alert type.

Event Name

The xdr_event.name for this alert type in the Interflow data is azure_federation_modified.

Key Fields and Relevant Data Points

  • initiatedBy.user.id — user ID who initiated the activity 
  • initiatedBy.app.servicePrincipalId — application and Service Principal ID that initiated the activity 
  • user.name — user name
  • activityDisplayName — activity display name
  • category — activity category
  • result — result of the activity
  • resultReason — result reason of the activity
  • stellar.rule_id — Stellar Cyber rule ID

Link to Rule-Based Alert Types

Rules Contributing to Microsoft Entra Federation Modified Alert Type

Analytics

N

Microsoft Entra Guest User Invited By Non-Approved Inviters

The Microsoft Entra Guest User Invited by Non-Approved Inviters rules are used to identify suspicious Microsoft Entra guest user invited by non-approved inviters. Any one or more of these will trigger the Microsoft Entra Guest User Invited by Non-Approved Inviters alert type.

Event Name

The xdr_event.name for this alert type in the Interflow data is azure_guest_user_invited_by_non_approved_inviters.

Key Fields and Relevant Data Points

  • initiatedBy.user.id — user ID who initiated the activity 
  • initiatedBy.app.servicePrincipalId — application and Service Principal ID that initiated the activity 
  • user.name — user name
  • activityDisplayName — activity display name
  • category — activity category
  • result — result of the activity
  • resultReason — result reason of the activity
  • stellar.rule_id — Stellar Cyber rule ID

Link to Rule-Based Alert Types

Rules Contributing to Microsoft Entra Guest User Invited by Non-Approved Inviters Alert Type

Analytics

N

Microsoft Entra ID Discovery Using AzureHound

The Microsoft Entra ID Discovery using AzureHound rules are used to identify Microsoft Entra ID discovery using Azurehound. Any one or more of these will trigger the Microsoft Entra ID Discovery using Azurehound alert type.

Event Name

The xdr_event.name for this alert type in the Interflow data is azure_discovery_using_azurehound.

Key Fields and Relevant Data Points

  • srcip_username — user name of the account involved in the event 
  • srcip — IP address of the login client
  • srcip_host — host name of the login client
  • UserAgent — user agent
  • stellar.rule_id — Stellar Cyber rule ID

Link to Rule-Based Alert Types

Rules Contributing to Microsoft Entra ID Discovery Using Azurehound Alert Type

Analytics

N

Microsoft Entra PIM Setting Changed

The Microsoft Entra PIM Setting Changed rules are used to identify suspicious Microsoft Entra PIM setting changed. Any one or more of these will trigger the Microsoft Entra PIM Setting Changed alert type.

Event Name

The xdr_event.name for this alert type in the Interflow data is azure_pim_setting_changed.

Key Fields and Relevant Data Points

  • initiatedBy.user.id — user ID who initiated the activity 
  • initiatedBy.app.servicePrincipalId — application and Service Principal ID that initiated the activity 
  • user.name — user name
  • activityDisplayName — activity display name
  • category — activity category
  • result — result of the activity
  • resultReason — result reason of the activity
  • stellar.rule_id — Stellar Cyber rule ID

Link to Rule-Based Alert Types

Rules Contributing to Microsoft Entra PIM Setting Changed Alert Type

Analytics

N

Microsoft Entra Privileged Account Assignment or Elevation

The Microsoft Entra Privileged Account Assignment or Elevation rules are used to identify suspicious Microsoft Entra privileged account assignment or elevation. Any one or more of these will trigger the Microsoft Entra Privileged Account Assignment or Elevation alert type.

Event Name

The xdr_event.name for this alert type in the Interflow data is azure_privileged_account_assignment_or_elevation.

Key Fields and Relevant Data Points

  • initiatedBy.user.id — user ID who initiated the activity 
  • initiatedBy.app.servicePrincipalId — application and Service Principal ID that initiated the activity 
  • user.name — user name
  • activityDisplayName — activity display name
  • category — activity category
  • result — result of the activity
  • resultReason — result reason of the activity
  • stellar.rule_id — Stellar Cyber rule ID

Link to Rule-Based Alert Types

Rules Contributing to Microsoft Entra Privileged Account Assignment or Elevation Alert Type

Analytics

N

Microsoft Entra Sign-in Failure

The Microsoft Entra Sign-in Failure rules are used to identify suspicious Microsoft Entra sign-in failures. Any one or more of these will trigger the Microsoft Entra Sign-in Failure alert type.

Event Name

The xdr_event.name for this alert type in the Interflow data is azure_sign_in_failures.

Key Fields and Relevant Data Points

  • srcip_username — user name of the account involved in the event 
  • srcip — IP address of the login client
  • srcip_host — host name of the login client
  • login_result — login result of user login events
  • azure_ad.status.failureReason — reason for the login failure
  • stellar.rule_id — Stellar Cyber rule ID

Link to Rule-Based Alert Types

Rules Contributing to Microsoft Entra Sign-in Failure Alert Type

Analytics

N

Microsoft Entra Suspicious Sign-in Activity

The Microsoft Entra Suspicious Sign-in Activity rules are used to identify suspicious Microsoft Entra sign-in activity. Any one or more of these will trigger the Microsoft Entra Suspicious Sign-in Activity alert type.

Event Name

The xdr_event.name for this alert type in the Interflow data is azure_suspicious_sign_in_activity.

Key Fields and Relevant Data Points

  • srcip_username — user name of the account involved in the event 
  • srcip — IP address of the login client
  • srcip_host — host name of the login client
  • login_result — login result of user login events
  • azure_ad.status.failureReason — reason for the login failure
  • stellar.rule_id — Stellar Cyber rule ID

Link to Rule-Based Alert Types

Rules Contributing to Suspicious Microsoft Entra Sign-In Activity Alert Type

Analytics

N

Microsoft Entra Unusual Account Creation

The Microsoft Entra Unusual Account Creation rules are used to identify Microsoft Entra unusual account creation activity. Any one or more of these will trigger the Microsoft Entra Unusual Account Creation alert type.

Event Name

The xdr_event.name for this alert type in the Interflow data is azure_unusual_account_creation.

Key Fields and Relevant Data Points

  • initiatedBy.user.id — user ID who initiated the activity 
  • initiatedBy.app.servicePrincipalId — application and Service Principal ID that initiated the activity 
  • user.name — user name
  • activityDisplayName — activity display name
  • category — activity category
  • result — result of the activity
  • resultReason — result reason of the activity
  • stellar.rule_id — Stellar Cyber rule ID

Link to Rule-Based Alert Types

Rules Contributing to Microsoft Entra Unusual Account Creation Alert Type

Analytics

N

Mimikatz Credential Dump

A potential Mimikatz memory dump was observed. Check the process to determine whether the host is compromised. Consider quarantining the host.

XDR Kill Chain

  • Kill Chain Stage: Propagation

  • Tactic: [Internal] Credential Access (TA0006 )

  • Technique: OS Credential Dumping (T1003 )

  • Tags: [Internal]

Event Name

The xdr_event.name for this alert type in the Interflow data is mimikatz_mem_scan.

Severity

90

Key Fields and Relevant Data Points

  • hostip — host IP address 
  • hostip_host — host name
  • access_subject — process attempting access  

  • access_mask — mask that the suspicious process used to obtain access privileges (different access masks indicate different capabilities obtained by the suspicious process)

Use Case with Data Points

If a process (access_subject) on a Windows host (srcip) tries to access lsass.exe with a special access mask (access_mask), an alert is triggered. The Interflow includes the IP address of the Windows host (srcip), the process performing mimikatz activity (access_subject), and the access mask used to acquire access privilege (access_mask).

Analytics

N

Mimikatz DCSync

An attempt to replicate Active Directory for the first time on a domain controller, or the first time by that account, has occurred. Evaluate whether the replication is intended and, if not, consider disabling the account involved in the replication and investigate for further signs of compromise.

XDR Kill Chain

  • Kill Chain Stage: Propagation

  • Tactic: [Internal] Credential Access (TA0006 )

  • Technique: OS Credential Dumping (T1003 )

  • Tags: [Internal, Active Directory]

Event Name

The xdr_event.name for this alert type in the Interflow data is mimikatz_dcsync.

Severity

90

Key Fields and Relevant Data Points

  • hostip — IP address of the targeted domain controller  
  • event_data.SubjectUserSid — source user ID associated with the account attempting replication  
  • hostip_host — host name of the targeted domain controller
  • event_data.SubjectUserName — name of the account that attempted the Active Directory replication
  • event_data.SubjectDomainName — domain of the account that attempted the Active Directory replication

Use Case with Data Points

This alert is triggered when replication of an Active Directory domain controller (hostip) occurs for the first time or is attempted by a user account or computer account (event_data.SubjectUserName) that has rarely occurred (days_silent) or never initiated replication on that DC before. The Interflow includes the IP address of the targeted domain controller (hostip), the account (event_data.SubjectUserName) attempting the replication and its domain (event_data.SubjectDomainName), and the replication operation attempted (event_data.Properties). (For guidance understanding the GUID in the event_data.Properties field, refer to Microsoft Documentation.)

Validation / Remediation

To triage an alert of this type, consider first verifying whether the Active Directory replication event was expected. If the replication is not intended, then the alert has indicated that a DCSync attack is highly likely. This attack can be very severe, because all password hashes stored on the targeted domain controller might have been dumped. Disable the account involved in the replication as soon as possible and further investigate the account for any signs of compromise.

There is no simple remediation for a confirmed DCSync attack. Evaluate the overall risks of credential leakage and apply appropriate corrective actions, including minimizing accounts with permissions to perform Active Directory replication, and forcing a change of credentials for accounts with weak passwords.

Potential False Positives

The following will trigger an alert:

  • Set up of a new  DC

  • Replication of a DC for the first time

Analytics

N

Office 365 Access Governance Anomaly

This alert type is deprecated as of the 4.3.7 release. It is replaced by Microsoft 365 alert integration. See Microsoft 365: Valid Accounts (Privilege Escalation) and Microsoft 365: Account Manipulation.

Office 365 generated an access governance alert, which might indicate a change in Exchange admin privileges. Check with the user to make sure this was expected.

XDR Kill Chain

  • Kill Chain Stage: Propagation

  • Tactic: Privilege Escalation (TA0004 )

  • Technique: Valid Accounts (T1078 )

  • Tags: []

Event Name

The xdr_event.name for this alert type in the Interflow data is office365_access_governance_alert.

Severity

75

Key Fields and Relevant Data Points

  • srcip_usersid — key ID for the Office 365 account  
  • Name — alert type description
  • Source — source that generated the alert seen by Stellar Cyber
  • srcip — source IP address
  • srcip_host — source host name

Use Case with Data Points

For each Office 365 account (srcip_usersid), access governance alerts detected by Office 365 are checked periodically. If Office 365 finds an access governance alert, an alert is triggered. A sample Interflow includes the account ID (srcip_usersid), this alert type description (Name),the alerting source (Source), and source IP address (srcip).

Analytics

N

Office 365 Admin Audit Logging Disabled

Office 365 admin audit logging was disabled. Make sure this change was expected.

XDR Kill Chain

  • Kill Chain Stage: Persistent Foothold

  • Tactic: Defense Evasion (TA0005 )

  • Technique: Impair Defenses (T1562 )

  • Tags: []

Event Name

The xdr_event.name for this alert type in the Interflow data is office365_admin_audit_logging_disabled.

Severity

60

Key Fields and Relevant Data Points

  • srcip_usersid — key ID for the Office 365 account  
  • OrganizationName — organization with audit logging

Use Case with Data Points

Office 365 monitors each Office 365 account (srcip_usersid) for admin audit logging status. If admin audit logging is disabled, an alert is triggered. A sample Interflow includes the account ID (srcip_usersid) and organization name (OrganizationName).

Analytics

N

Office 365 Blocked User

This alert type is deprecated as of the 4.3.7 release. It is replaced by Microsoft 365 alert integration. See Microsoft 365: Valid Accounts (Initial Access).

The Office 365 Security Compliance Center discovered a user exceeding the sending limits of the service or outbound spam policies and blocked the user from sending email. Check with the user.

XDR Kill Chain

  • Kill Chain Stage: Initial Attempts

  • Tactic: [External] XDR UBA (XTA0004)

  • Technique: XDR Suspicious User (XT4008)

  • Tags: [External]

Event Name

The xdr_event.name for this alert type in the Interflow data is office365_blocked_user.

Severity

40

Key Fields and Relevant Data Points

  • srcip_usersid — key ID for the Office 365 account 
  • Source — alerting source
  • srcip — source IP address of the account
  • srcip_host — source host name

Use Case with Data Points

Office 365 monitors email sending actions for each Office 365 account (srcip_usersid). If an account exceeds the sending limit, an alert is triggered. A sample Interflow includes the account ID (srcip_usersid), alerting source (Source), and source IP address (srcip).

Analytics

N

Office 365 Content Filter Policy Changed

The Microsoft Exchange content policy was changed. An overly permissive content policy can allow spammers to send your organization unwanted email. Make sure this change was expected.

XDR Kill Chain

  • Kill Chain Stage: Persistent Foothold

  • Tactic: Persistence (TA0003 )

  • Technique: Account Manipulation (T1098 )

  • Tags: []

Event Name

The xdr_event.name for this alert type in the Interflow data is office365_content_filter_policy_changed.

Severity

40

Key Fields and Relevant Data Points

  • srcip_usersid — key ID for the Office 365 account  
  • OrganizationId — ID of the organization with the Microsoft content policy change 
  • OrganizationName — organization with the Microsoft content policy change

Use Case with Data Points

Office 365 monitors all Office 365 accounts (srcip_usersid) in each organization (OrganizationId) for a Microsoft Exchange content policy change. If a change is detected, an alert is triggered. A sample Interflow includes the Office 365 account ID (srcip_usersid), organization ID (OrganizationId), and organization name (OrganizationName).

Analytics

N

Office 365 Data Exfiltration Attempt Anomaly

This alert type is deprecated as of the 4.3.7 release. It is replaced by Microsoft 365 alert integration. See Microsoft 365: Exfiltration Over Web Service.

The Office 365 Security Compliance Center discovered a data exfiltration attempt. Office 365 then blocked, quarantined, encrypted, or applied a hold on the possible exfiltration. Check with the user.

XDR Kill Chain

  • Kill Chain Stage: Exfiltration & Impact

  • Tactic: Exfiltration (TA0010 )

  • Technique: Exfiltration Over Web Service (T1567 )

  • Tags: []

Event Name

The xdr_event.name for this alert type in the Interflow data is office365_data_exfiltration_attempt.

Severity

90

Key Fields and Relevant Data Points

  • srcip_usersid — key ID for the Office 365 account  
  • Name — alert type description
  • Source — reporting source
  • srcip — source IP address
  • srcip_host — source host name

Use Case with Data Points

Office 365 periodically checks each Office 365 account (srcip_usersid) for data exfiltration attempts. If data exfiltration is detected, an alert is triggered. A sample Interflow includes the account ID (srcip_usersid), this alert type description (Name), reporting source (Source), and source IP address (srcip).

Analytics

N

Office 365 Data Loss Prevention

This alert type is deprecated as of the 4.3.7 release. It is replaced by Microsoft 365 alert integration. See Microsoft 365: Exfiltration Over Web Service.

The Office 365 Security Compliance Center discovered data loss. Office 365 then blocked, quarantined, encrypted, or applied a hold on the possible exfiltration. Check with the user.

XDR Kill Chain

  • Kill Chain Stage: Exfiltration & Impact

  • Tactic: Exfiltration (TA0010 )

  • Technique: Exfiltration Over Web Service (T1567 )

  • Tags: []

Event Name

The xdr_event.name for this alert type in the Interflow data is office365_data_loss_prevention.

Severity

90

Key Fields and Relevant Data Points

  • srcip_usersid — key ID for the Office 365 account  
  • Name — alert type description
  • Source — reporting source
  • srcip — source IP address
  • srcip_host — source host name

Use Case with Data Points

Office 365 periodically checks each Office 365 account (srcip_usersid) for data loss. If data loss is detected, an alert is triggered. A sample Interflow includes the account ID (srcip_usersid), this alert type description (Name), reporting source (Source), and source IP address (srcip).

Analytics

N

Office 365 File Sharing with Outside Entities

An Office 365 account shared multiple files with entities outside of the organization. Check with the user to make sure this was expected.

XDR Kill Chain

  • Kill Chain Stage: Exfiltration & Impact

  • Tactic: Exfiltration (TA0010 )

  • Technique: Transfer Data to Cloud Account (T1537 )

  • Tags: []

Event Name

The xdr_event.name for this alert type in the Interflow data is office365_outside_entity_file_sharing.

Severity

50

Key Fields and Relevant Data Points

  • srcip_usersid — key ID for the Office 365 account 
  • srcip — source IP address of the sharing action
  • srcip_host — source host name
  • srcip_geo.countryName — source country

Use Case with Data Points

Office 365 monitors sharing with outside entities for each Office 365 account (srcip_usersid). If an account shares multiple files with outside entities, an alert is triggered. A sample Interflow includes the user ID (srcip_usersid), source IP address (srcip), and source country (srcip_geo.countryName).

Analytics

N

Office 365 Malware Filter Policy Changed

The Microsoft Exchange malware filter policy changed. An overly permissive malware filter policy can allow attackers to send malicious attachments to your organization. Make sure this change was expected.

XDR Kill Chain

  • Kill Chain Stage: Persistent Foothold

  • Tactic: Defense Evasion (TA0005 )

  • Technique: Impair Defenses (T1562 )

  • Tags: []

Event Name

The xdr_event.name for this alert type in the Interflow data is office365_malware_filter_policy_changed.

Severity

50

Key Fields and Relevant Data Points

  • srcip_usersid — key ID for the Office 365 account  
  • OrganizationId — ID of the organization with the Microsoft Exchange malware policy change 
  • OrganizationName — organization with the Microsoft Exchange malware policy change

Use Case with Data Points

Office 365 monitors all Office 365 accounts (srcip_usersid) in every organization (OrganizationId) for Microsoft Exchange malware policy changes. If a change is discovered, an alert is triggered. A sample Interflow includes the account ID (srcip_usersid), organization ID (OrganizationId), and organization name (OrganizationName).

Analytics

N

Office 365 Multiple Files Restored

Office 365 observed that multiple files were restored in a short period. Check with the user.

XDR Kill Chain

  • Kill Chain Stage: Exploration

  • Tactic: Collection (TA0009 )

  • Technique: Data Staged (T1074 )

  • Tags: []

Event Name

The xdr_event.name for this alert type in the Interflow data is office365_multi_file_restore.

Severity

50

Key Fields and Relevant Data Points

  • srcip_usersid — key ID for the Office 365 account 
  • EventSource — event source
  • srcip — source IP address that caused the restore
  • srcip_host — source host name

Use Case with Data Points

Office 365 periodically checks file restore records. If multiple file restore records are detected within a short period, an alert is triggered. A sample Interflow includes the Office 365 account ID (srcip_usersid), event source (EventSource), and source IP address (srcip).

Analytics

N

Office 365 Multiple Users Deleted

Office 365 observed that multiple users were deleted in a short period. Check with the user.

XDR Kill Chain

  • Kill Chain Stage: Exfiltration & Impact

  • Tactic: Impact (TA0040 )

  • Technique: Account Access Removal (T1531 )

  • Tags: []

Event Name

The xdr_event.name for this alert type in the Interflow data is office365_multi_user_deleted.

Severity

50

Key Fields and Relevant Data Points

  • srcip_usersid — key ID for the Office 365 account 
  • EventSource — event source
  • srcip — source IP address that did the deletion
  • srcip_host — source host name

Use Case with Data Points

Office 365 periodically checks user deletion records. If multiple users were deleted within a short period, an alert is triggered. A sample Interflow includes the Office 365 account ID (srcip_usersid), event source (EventSource), and source IP address (srcip).

Analytics

N

Office 365 Network Security Configuration Changed

Office 365 identified a change to your organization's network security configuration, which is uncommon. Make sure this was expected.

XDR Kill Chain

  • Kill Chain Stage: Persistent Foothold

  • Tactic: Persistence (TA0003 )

  • Technique: Account Manipulation (T1098 )

  • Tags: []

Event Name

The xdr_event.name for this alert type in the Interflow data is office365_security_conf_changed.

Severity

70

Key Fields and Relevant Data Points

  • srcip_usersid — key ID for ther Office 365 account 
  • OrganizationId — ID of the organization whose security configuration changed 
  • OrganizationName — name of the organization whose security configuration changed

Use Case with Data Points

Office 365 monitors all Office 365 accounts (srcip_usersid) in every organization (OrganizationId) for network security configuration changes. If a change is detected, an alert is triggered. A sample Interflow includes the Office 365 account ID (srcip_usersid), organization ID (OrganizationId), and organization name (OrganizationName).

Analytics

N

Office 365 Password Policy Changed

Office 365 identified a change to your organization's password policy, which is uncommon. Make sure this was expected.

XDR Kill Chain

  • Kill Chain Stage: Persistent Foothold

  • Tactic: Defense Evasion (TA0005 )

  • Technique: Modify Authentication Process (T1556 )

  • Tags: []

Event Name

The xdr_event.name for this alert type in the Interflow data is office365_password_policy_changed.

Severity

40

Key Fields and Relevant Data Points

  • srcip_usersid — key ID for the Office 365 account 
  • OrganizationId — ID of the organization whose password policy changed 
  • OrganizationName — name of the organization whose password policy changed

Use Case with Data Points

Office 365 monitors all Office 365 accounts (srcip_usersid) in every organization (OrganizationId) for sharing policy changes. If a change is detected, an alert is triggered. A sample Interflow includes the account ID (srcip_usersid), organization ID (OrganizationId), and organization name (OrganizationName).

Analytics

N

Office 365 Sharing Policy Changed

Office 365 identified a change to your organization's sharing policy, which is uncommon. Make sure this was expected.

XDR Kill Chain

  • Kill Chain Stage: Persistent Foothold

  • Tactic: Persistence (TA0003 )

  • Technique: Account Manipulation (T1098 )

  • Tags: []

Event Name

The xdr_event.name for this alert type in the Interflow data is office365_sharing_policy_changed.

Severity

60

Key Fields and Relevant Data Points

  • srcip_usersid — key ID for the Office 365 account 
  • OrganizationId — ID of the organization whose sharing policy changed 
  • OrganizationName — name of the organization whose sharing policy changed

Use Case with Data Points

Office 365 monitors all Office 365 accounts (srcip_usersid) in every organization (OrganizationId) for password policy changes. If a change is detected, an alert is triggered. A sample Interflow includes the Office 365 account ID (srcip_usersid), organization ID (OrganizationId), and organization name (OrganizationName).

Analytics

N

Office 365 User Network Admin Changed

The Office 365 account’s network admin information was changed. Make sure this change was expected.

XDR Kill Chain

  • Kill Chain Stage: Persistent Foothold

  • Tactic: Persistence (TA0003 )

  • Technique: Account Manipulation (T1098 )

  • Tags: []

Event Name

The xdr_event.name for this alert type in the Interflow data is office365_user_network_admin_changed.

Severity

50

Key Fields and Relevant Data Points

  • srcip_usersid — key ID for the Office 365 account 
  • OrganizationName — name of the organization

Use Case with Data Points

Office 365 monitors the network admin information for each Office 365 account (srcip_usersid). If changes to the network admin are discovered, an alert is triggered. A sample Interflow includes the account ID (srcip_usersid) and organization name (OrganizationName).

Analytics

N

Outbound Destination Country Anomaly

A host that typically communicates with a small, consistent number of countries communicated with a new country. Investigate the destination, to see if it is benign.

XDR Kill Chain

  • Kill Chain Stage: Initial Attempts

  • Tactic: [External] XDR NBA (XT2005)

  • Technique: XDR Location Anomaly (XT2001)

  • Tags: [External; Network Traffic Analysis]

Event Name

The xdr_event.name for this alert type in the Interflow data is country_communication_anomaly.

Severity

20

Key Fields and Relevant Data Points

  • srcip — source IP address  
  • dstip_geo.countryName — name of the destination country 
  • dstip — destination IP address
  • srcip_host — host name of corresponding source IP address
  • dstip_host — host name of corresponding destination IP address
  • appid_name — application name
  • stability — score measuring the time since the host communicated with the last new country
  • days_stable — time since the host communicated with the last new country
  • diversity — score measuring the number of countries with which the host communicated
  • child_count — number of countries with which the host communicated

Use Case with Data Points

Hosts (srcip_host) and destination countries (dstip_geo.countryName) are examined periodically. If a host (srcip_host) with a small number of destination countries (diversity, child_count) has not visited a new country for a long time (stability, days_stable) visits a host (dstip_host) in a new country with an application (appid_name), an alert is triggered.

Unsupervised

Y

Outbytes Anomaly

A source IP address transmitted an anomalously high amount of outbound traffic to one or multiple destination addresses in a 5 minute interval. This could indicate data exfiltration.

Firewall and non-firewall data do not contribute to the same alert, so this alert will have either entirely firewall data or no firewall data.

XDR Kill Chain

  • Kill Chain Stage: Exfiltration & Impact

  • Tactic: Exfiltration (TA0010 )

  • Technique: Automated Exfiltration (T1020 )

  • Tags: [Network Traffic Analysis]

Event Name

The xdr_event.name for this alert type in the Interflow data is outbytes_anomaly.

Severity

35

Key Fields and Relevant Data Points

  • srcip_host — source host name 
  • srcip — source IP address
  • actual — actual amount of outbound traffic in the period
  • typical — typical amount of outbound traffic from the source IP address
  • dstip_host — destination host name

Use Case with Data Points

Every source host's (srcip_host) transferred data volume is calculated periodically. If a host's volume (actual) is much higher than its normal volume (typical) in any period, an alert is triggered. The Interflow includes the destination host (dstip_host).

Unsupervised

Y

Password Cracking with Hashcat

A user from a Windows host executed a command-line script that launched either the hashcat.exe command or a command using known Hashcat parameters (-a -m 1000 -r). The Hashcat command is known to use a SAM file from the Windows registry along with a password list to crack passwords.

XDR Kill Chain

  • Kill Chain Stage: Propagation

  • Tactic: [Internal] Credential Access (TA0006 )

  • Technique: Brute Force (T1110 )

  • Tags: [Hashcat]

Event Name

The xdr_event.name for this alert type in the Interflow data is password_cracking_with_hashcat.

Severity

90

Key Fields and Relevant Data Points

  • hostip — device internal IP address  
  • event_data.Image — process running the hashcat tool  
  • event_data.CommandLine — command used to run the tool  
  • computer_name — name of the Windows host

Use Case with Data Points

This alert is triggered if a Windows host (hostip) executes a PowerShell script with a context that includes one or more flags (event_data.Image or event_data.CommandLine) indicating usage of the Hashcat password cracking tool. The Interflow includes the IP address of the Windows host (hostip), the host name (computer_name), and the script image (event_data.Image) or script payload (event_data.CommandLine).

Validation / Remediation

Check the body of the Powershell script that is reported on the Windows host to identify whether the contents are actually malicious. If malicious, consider quarantining the host.

Potential False Positives

The running of any executable named hashcat.exe or any command that uses the hashcat signature parameter list (-a -m 1000 -r).

Analytics

N

Password Spraying Attempts Using Dsacls

A user from a Windows host executed a command-line script to launch a command that by name and parameter list indicates an attempt to abuse dsacls.exe for password spraying.

XDR Kill Chain

  • Kill Chain Stage: Initial Attempts

  • Tactic: [Internal] Defense Evasion (TA0005 )

  • Technique: System Binary Proxy Execution (T1218)

  • Tags: [Password Spray;Dsacls]

Event Name

The xdr_event.name for this alert type in the Interflow data is password_spraying_attempts_using_dsacls.

Severity

50

Key Fields and Relevant Data Points

  • hostip — device internal IP address  
  • event_data.Image — process running dsacls for password cracking  
  • event_data.CommandLine — command used to run the tool  
  • event_data.OriginalFileName — actual file name that was executed  
  • computer_name — name of the Windows host

Use Case with Data Points

This alert is triggered if a Windows host (hostip) executes a dsacls.exe with a context that includes one or more flags (event_data.Image, event_data.CommandLine, or event_data.OriginalFileName including /user and /passwd as parameters). This indicates possible usage of Dcacls as a password spraying tool. The Interflow includes the IP address of the Windows host (hostip), the host name (computer_name), and the script image (event_data.Image) or the original file name (event_data.OriginalFileName), and script commandline (event_data.CommandLine).

Validation / Remediation

Check whether the usage was actually malicious. If so, consider quarantining the Windows host.

Potential False Positives

This alert could be triggered even if the use is a legitimate use of dsacls to bind to an LDAP session.

Analytics

N

Phishing URL

A connection to a site with a phishing reputation was observed. Check with the user to determine whether their system is compromised.

XDR Kill Chain

  • Kill Chain Stage: Initial Attempts

  • Tactic: Initial Access (TA0001 )

  • Technique: Phishing (T1566 )

  • Tags: [Phishing; Network Traffic Analysis]

Event Name

The xdr_event.name for this alert type in the Interflow data is phishing.

Severity

30

Key Fields and Relevant Data Points

  • srcip — source IP address of the connection to the phishing URL reputation site  
  • dstip — destination IP address of the phishing URL reputation site  
  • url — URL of the phishing site  
  • dstip_host — destination host name 
  • metadata.response.subject_alt_name — Subject Alternative Name of the phishing site  
  • username — name of the visitor  
  • dstip_geo.countryName — destination country
  • srcip_host — source host name

Use Case with Data Points

If a connection from a source (scrip) to a site with a phishing reputation is detected, an alert is triggered. The Interflow includes the source IP address (srcip), source host (srcip_host), destination IP address (dstip), destination host (dstip_host), URL of the site (url), destination country (dstip_geo.countryName), Subject Alternative Name of the site (metadata.response.subject_alt_name), and user name (username).

Analytics

N

Possible Encrypted Phishing Site Visit

A possible phishing site visit to a recently registered domain was observed in encrypted traffic. Check with the user to determine whether their system is compromised.

XDR Kill Chain

  • Kill Chain Stage: Initial Attempts

  • Tactic: Initial Access (TA0001 )

  • Technique: Phishing (T1566 )

  • Tags: [Phishing; Network Traffic Analysis]

Event Name

The xdr_event.name for this alert type in the Interflow data is encrypted_phishing_site.

Severity

30

Key Fields and Relevant Data Points

  • metadata.response.effective_tld — effective top-level domain of the possible phishing site  
  • srcip — IP address of the visitor to the possible phishing site  
  • dstip — IP address of the possible phishing site  
  • srcip_host — source host name
  • dstip_host — destination host name
  • dstip_geo.countryName — destination country

Use Case with Data Points

If an encrypted connection to a recently registered site (metadata.response.effective_tld) is observed, an alert is triggered. The Interflow includes the source IP address (srcip), source host (srcip_host), destination IP address (dstip), destination host (dstip_host), destination country (dstip_geo.countryName), and effective top-level domain of the site (metadata.response.effective_tld).

Analytics

N

Possible Phishing Site Visit from Email

A user visited a recently registered domain shortly after using email, indicating a possible phishing site visit. Check to see if the site is malicious. If so, check with the user to see if they are compromised.

XDR Kill Chain

  • Kill Chain Stage: Initial Attempts

  • Tactic: Initial Access (TA0001 )

  • Technique: Phishing (T1566 )

  • Tags: [Phishing; Network Traffic Analysis]

Event Name

The xdr_event.name for this alert type in the Interflow data is email_recent_domain_correlation.

Severity

70

Key Fields and Relevant Data Points

  • recent_domain_id — ID that points to the original record of the recently registered domain visit
  • email_traffic_id — ID that points to the original record of email traffic
  • correlation_info.appid_name — application on the visited domain accessed by the user
  • correlation_info.srcip — IP address of the user
  • correlation_info.dstip — IP address of the recently registered domain (useful if the correlation_info.appid_name is not DNS)
  • correlation_info.dstip_host — recently registered domain that was visited (useful if the correlation_info.appid_name is not DNS)
  • correlation_info.metadata.response.query — recently registered domain name the victim queried in DNS traffic (useful if the correlation_info.appid_name is DNS)

  • correlation_info.metadata.response.resolved_ips — IPs of the recently registered domain name the victim queried in DNS traffic. This field only useful if correlation_info.appid_name is DNS.

Use Case with Data Points

If a user (srcip) uses email (appid_name) and then either queries a recently registered (metadata.response.domain_creation) domain (metadata.response.query) or visits a recently registered (dstip_domain_creation) domain (dstip_host), an alert is triggered.

When an alert is triggered, a new correlation event is created. The Interflow includes the reference ID of the original record of the domain visit (recent_domain_id), the reference ID pointing to the original record of email traffic (email_traffic_id), the IP address of the user (correlation_info.srcip), the application involved in the recently registered site visit (correlation_info.appid_name), and the visited domain (correlation_info.dstip_host or correlation_info.metadata.response.query).

Analytics

N

Possible Unencrypted Phishing Site Visit

A possible phishing site visit to a recently registered domain was observed in unencrypted traffic. Check with the user to determine whether their system is compromised.

XDR Kill Chain

  • Kill Chain Stage: Initial Attempts

  • Tactic: Initial Access (TA0001 )

  • Technique: Phishing (T1566 )

  • Tags: [Phishing; Network Traffic Analysis]

Event Name

The xdr_event.name for this alert type in the Interflow data is unencrypted_phishing_site.

Severity

30

Key Fields and Relevant Data Points

  • metadata.response.effective_tld — effective top-level domain of the possible phishing site
  • srcip — IP address of the visitor to the phishing site  
  • dstip — IP address of the possible phishing site  
  • srcip_host — source host name
  • dstip_host — destination host name
  • dstip_geo.countryName — destination country

Use Case with Data Points

If an unencrypted connection to a recently registered site (metadata.response.effective_tld) is detected, an alert is triggered. The Interflow includes the source IP address (srcip), source host (srcip_host), destination IP address (dstip), destination host (dstip_host), destination country (dstip_geo.countryName), and effective top-level domain of the site (metadata.response.effective_tld).

Analytics

N

Potentially Malicious AWS Activity

The Potentially Malicious AWS Activity rules are used to identify suspicious activity within AWS logs. Any one or more of these will trigger the Potentially Malicious AWS Activity alert type.

Event Name

The xdr_event.name for this alert type in the Interflow data is aws_malicious_activity.

Key Fields and Relevant Data Points

  • eventSource — source of event 
  • eventName — name of event 
  • eventType — type of event
  • userIdentity.accountId — key ID for the account involved in the event
  • userIdentity.userName — user name of the account involved in the event
  • userIdentity.type — type of account involved in the event
  • stellar.rule_id — Stellar Cyber rule ID

Link to Rule-Based Alert Types

Rules Contributing to Potentially Malicious AWS Activity Alert Type

Analytics

N

Potentially Malicious Windows Event

The Potentially Malicious Windows Event rules are used to identify suspicious activity with Windows Events. This is a generic rule name. Any one or more of these will trigger the Potentially Malicious Windows Event alert type.

Event Name

The xdr_event.name for this alert type in the Interflow data is windows_security_malicious_event.

Key Fields and Relevant Data Points

  • event_id — Windows event ID associated with the activity 
  • hostip — host IP address 
  • hostip_host — host name
  • stellar.rule_id — Stellar Cyber rule ID

Link to Rule-Based Alert Types

Rules Contributing to Potentially Malicious Event Alert Type

Analytics

N

PowerShell Remote Access

A Windows host executed a PowerShell script interacting with a remote host. Investigate the script and the remote host to determine whether the script is malicious. If so, consider quarantining the host.

XDR Kill Chain

  • Kill Chain Stage: Persistent Foothold

  • Tactic: Execution (TA0002 )

  • Technique: Command and Scripting Interpreter (T1059 )

  • Tags: []

Event Name

The xdr_event.name for this alert type in the Interflow data is powershell_cnc.

Severity

80

Key Fields and Relevant Data Points

  • hostip — IP address of the Windows host 
  • hostip_host — host name
  • remote_ip — IP address of the remote host involved in the script 
  • event_data.ScriptBlockText — contents of the PowerShell script

Use Case with Data Points

If a Windows host (srcip) executes a PowerShell script that includes potential communication (event_data.ScriptBlockText) with a remote host (remote_ip), an alert is triggered. The Interflow includes the IP address of the Windows host (srcip), the script body (event_data.ScriptBlockText), and the remote host IP address (remote_ip).

Analytics

N

Private to Private Exploit Anomaly

A private IP address initiated a large number of exploit attempts identified by a given signature or a rarely seen exploit attempt to another private IP address. Investigate that signature.

XDR Kill Chain

  • Kill Chain Stage: Propagation

  • Tactic: [Internal] Lateral Movement (TA0008 )

  • Technique: Exploitation of Remote Services (T1210 )

  • Tags: [Internal; Network Traffic Analysis]

Event Name

The xdr_event.name for this alert type in the Interflow data is exploit_attempt_priv_priv.

Severity

75

Key Fields and Relevant Data Points

  • ids.signature — signature of the exploit  
  • ids.severity — severity of the exploit
  • actual — actual number of times this signature was found in the period, with critical IDS signatures counted as 2, high counted as 1, low counted as 0.5, and others counted as 1
  • typical — typical number of times this signature is seen in the period, with critical IDS signatures counted as 2, high counted as 1, low counted as 0.5, and others counted as 1
  • srcip_host — host name of corresponding source IP address
  • dstip_host — host name of corresponding destination IP address

Use Case with Data Points

The occurrences of each malware (ids.signature) and severity (ids.severity) are calculated periodically. If one malware occurs much more often (actual) than its history (typical) in any period, an alert is triggered. The Interflow includes the source host (srcip_host) and destination host (dstip_host).

Unsupervised

Y

Private to Public Exploit Anomaly

A private IP address initiated a large number of exploit attempts identified by a given signature or a rarely seen exploit attempt to a public IP address. Investigate that signature.

XDR Kill Chain

  • Kill Chain Stage: Initial Attempts

  • Tactic: [External] Initial Access (TA0001 )

  • Technique: Exploit Public-Facing Application (T1190 )

  • Tags: [External; Network Traffic Analysis]

Event Name

The xdr_event.name for this alert type in the Interflow data is exploit_attempt_priv_pub.

Severity

60

Key Fields and Relevant Data Points

  • ids.signature — signature of the exploit  
  • ids.severity — severity of the exploit
  • actual — actual number of times this signature was found in the period, with critical IDS signatures counted as 2, high counted as 1, low counted as 0.5, and others counted as 1
  • typical — typical number of times this signature is seen in the period, with critical IDS signatures counted as 2, high counted as 1, low counted as 0.5, and others counted as 1
  • srcip_host — host name of corresponding source IP address
  • dstip_host — host name of corresponding destination IP address

Use Case with Data Points

The occurrences of each malware (ids.signature) and severity (ids.severity) are calculated periodically. If one malware occurs much more often (actual) than its history (typical) in any period, an alert is triggered. The Interflow includes the source host (srcip_host) and destination host (dstip_host).

Unsupervised

Y

Process Anomaly

A process has been launched an anomalously large number of times. Investigate the process and the user to see if this is expected.

XDR Kill Chain

  • Kill Chain Stage: Persistent Foothold

  • Tactic: XDR EBA (XTA0001)

  • Technique: XDR Process Anomaly (XT1001)

  • Tags: []

Event Name

The xdr_event.name for this alert type in the Interflow data is bad_process.

Severity

15

Key Fields and Relevant Data Points

  • process_name — name of the process 
  • hostip — host IP address
  • hostip_host — host name
  • actual — actual number of launches in the period
  • typical — typical number of launches in the period

Use Case with Data Points

The number of times a process (process_name) has been launched is calculated periodically. If the volume (actual) is much larger than the typical volume (typical) of the command or other commands in any period, an alert is triggered. The Interflow includes the (hostip) who launched the process.

Unsupervised

Y

Public to Private Exploit Anomaly

A public IP address initiated a large number of exploit attempts identified by a given signature or a rarely seen exploit attempt to a private IP address. Investigate that signature.

XDR Kill Chain

  • Kill Chain Stage: Initial Attempts

  • Tactic: [External] Initial Access (TA0001 )

  • Technique: Exploit Public-Facing Application (T1190 )

  • Tags: [External; Network Traffic Analysis]

Event Name

The xdr_event.name for this alert type in the Interflow data is exploit_attempt_pub_priv.

Severity

60

Key Fields and Relevant Data Points

  • ids.signature — signature of the exploit  
  • ids.severity — severity of the exploit
  • actual — actual number of times this signature was found in the period, with critical IDS signatures counted as 2, high counted as 1, low counted as 0.5, and others counted as 1
  • typical — typical number of times this signature is seen in the period, with critical IDS signatures counted as 2, high counted as 1, low counted as 0.5, and others counted as 1
  • srcip_host — host name of corresponding source IP address
  • dstip_host — host name of corresponding destination IP address

Use Case with Data Points

The occurrences of each malware (ids.signature) and severity (ids.severity) are calculated periodically. If one malware occurs much more often (actual) than its history (typical) in any period, an alert is triggered. The Interflow includes the source host (srcip_host) and destination host (dstip_host).

Unsupervised

Y

Public to Public Exploit Anomaly

A public IP address initiated a large number of exploit attempts identified by a given signature or a rarely seen exploit attempt to another public IP address. Investigate that signature.

XDR Kill Chain

  • Kill Chain Stage: Initial Attempts

  • Tactic: [External] Initial Access (TA0001 )

  • Technique: Exploit Public-Facing Application (T1190 )

  • Tags: [External; Network Traffic Analysis]

Event Name

The xdr_event.name for this alert type in the Interflow data is exploit_attempt_pub_pub.

Severity

50

Key Fields and Relevant Data Points

  • ids.signature — signature of the exploit  
  • ids.severity — severity of the exploit
  • actual — actual number of times this signature was found in the period, with critical IDS signatures counted as 2, high counted as 1, low counted as 0.5, and others counted as 1
  • typical — typical number of times this signature is seen in the period, with critical IDS signatures counted as 2, high counted as 1, low counted as 0.5, and others counted as 1
  • srcip_host — host name of corresponding source IP address
  • dstip_host — host name of corresponding destination IP address

Use Case with Data Points

The occurrences of each malware (ids.signature) and severity (ids.severity) are calculated periodically. If one malware occurs much more often (actual) than its history (typical) in any period, an alert is triggered. The Interflow includes the source host (srcip_host) and destination host (dstip_host).

Unsupervised

Y

RDP Outbytes Anomaly

An internal host transferred an anomalously high amount of data to external host(s) through RDP. This could indicate data exfiltration. Check with the user.

XDR Kill Chain

  • Kill Chain Stage: Exfiltration & Impact

  • Tactic: Exfiltration (TA0010 )

  • Technique: Exfiltration Over Alternative Protocol (T1048 )

  • Tags: [Network Traffic Analysis]

Event Name

The xdr_event.name for this alert type in the Interflow data is rdp_outbytes_anomaly.

Severity

30

Key Fields and Relevant Data Points

  • dstip — destination IP address  
  • dstip_host — destination host name
  • actual — actual amount of outbound traffic in the period
  • typical — typical amount of outbound traffic from the destination IP address
  • srcip_host — source IP address that initiates the RDP connection

Use Case with Data Points

Every destination host's (dstip) transferred data volume through RDP is calculated periodically. If a host's volume (actual) is much greater than normal (typical) in any period, an alert is triggered. A sample Interflow includes the destination host (dstip_host).

Unsupervised

Y

RDP Port Opening

Netsh commands to open TCP port 3389 were observed. This could indicate Sarwent malware attempting to establish an RDP connection. Check the IP address and block if necessary.

XDR Kill Chain

  • Kill Chain Stage: Persistent Foothold

  • Tactic: Defense Evasion (TA0005 )

  • Technique: Impair Defenses (T1562 )

  • Tags: [RDP]

Event Name

The xdr_event.name for this alert type in the Interflow data is rdp_port_opening.

Severity

50

Key Fields and Relevant Data Points

  • hostip — source IP address that executes the command 
  • hostip_host — host name
  • event_data.CommandLine — command that was executed
  • process_name — process name

Use Case with Data Points

Commands that open TCP port 3389 are monitored, and if netsh commands are seen, an alert is triggered. A sample Interflow includes the source IP address (hostip) and the command used (event_data.CommandLine).

Analytics

N

RDP Registry Modification

Modifications of the property values of fDenyTSConnections and UserAuthentication to enable remote desktop connections were observed. Check the IP address and block if necessary.

XDR Kill Chain

  • Kill Chain Stage: Persistent Foothold

  • Tactic: Defense Evasion (TA0005 )

  • Technique: Modify Registry (T1112 )

  • Tags: [RDP]

Event Name

The xdr_event.name for this alert type in the Interflow data is rdp_registry_modification.

Severity

50

Key Fields and Relevant Data Points

  • hostip — IP address of the host that made the setting change 
  • hostip_host — host name
  • event_data.TargetObject — name of the registry key
  • event_data.Details — value of the registry

Use Case with Data Points

The property values of fDenyTSConnections and UserAuthentication are monitored, and if a possible malicious modification of the settings to enable remote desktop connections is observed, an alert is triggered. A sample Interflow includes the source IP address (hostip) and the registry name (event_data.TargetObject).

Analytics

N

RDP Reverse Tunnel

An svchost hosting RDP termsvcs communicating with the loopback address on TCP port 3389 was observed. Check the IP address and block if necessary.

XDR Kill Chain

  • Kill Chain Stage: Persistent Foothold

  • Tactic: Command and Control (TA0011 )

  • Technique: Protocol Tunneling (T1572 )

  • Tags: [RDP]

Event Name

The xdr_event.name for this alert type in the Interflow data is rdp_reverse_tunnel.

Severity

80

Key Fields and Relevant Data Points

  • hostip — host IP address  
  • hostip_host — host name
  • event_data.Image — process communicating with the loopback address

Use Case with Data Points

If an svchost hosting RDP termsvcs communicating with the loopback address is found on TCP port 3389, an alert is triggered. A sample Interflow includes the host IP address (hostip) and host name (hostip_host).

Analytics

N

RDP Session Hijacking

A suspicious RDP session using tscon.exe or MSTSC shadowing was observed. This could indicate a hijacked RDP session. Check the IP address and block if necessary.

XDR Kill Chain

  • Kill Chain Stage: Propagation

  • Tactic: Lateral Movement (TA0008 )

  • Technique: Remote Service Session Hijacking (T1563 )

  • Tags: [RDP]

Event Name

The xdr_event.name for this alert type in the Interflow data is rdp_session_hijacking.

Severity

50

Key Fields and Relevant Data Points

  • hostip — host IP address that executes the command 
  • hostip_host — host name
  • event_data.CommandLine — command line used
  • process_name — process name

Use Case with Data Points

If an RDP session redirect using tscon.exe or MSTSC is detected, an alert is triggered. A sample Interflow includes the host IP address (hostip), name of the process used (process_name), and command used (event_data.CommandLine).

Analytics

N

RDP Settings Hijacking

Changes to RDP terminal services settings were observed. Check the IP address and block if necessary.

XDR Kill Chain

  • Kill Chain Stage: Persistent Foothold

  • Tactic: Defense Evasion (TA0005 )

  • Technique: Modify Registry (T1112 )

  • Tags: [RDP]

Event Name

The xdr_event.name for this alert type in the Interflow data is rdp_settings_hijack.

Severity

50

Key Fields and Relevant Data Points

  • hostip — IP address of the host that made the setting change  
  • hostip_host — host name
  • event_data.TargetObject — name of the registry key

  • event_data.EventType — event type on the registry key (SetValue, DeleteValue)

  • event_data.Details — value of the registry

Use Case with Data Points

RDP terminal service settings are monitored, and if changes are found to these settings, an alert is triggered. A sample Interflow includes the source IP address (hostip) and the registry name (event_data.TargetObject).

Analytics

N

RDP Suspicious Logon

An RDP logon with a local source IP address was observed. This could indicate a tunneled logon. Check with the user.

XDR Kill Chain

  • Kill Chain Stage: Persistent Foothold

  • Tactic: Command and Control (TA0011 )

  • Technique: Protocol Tunneling (T1572 )

  • Tags: [RDP]

Event Name

The xdr_event.name for this alert type in the Interflow data is rdp_suspicious_logon.

Severity

75

Key Fields and Relevant Data Points

  • hostip — host IP address of the RDP server  
  • event_data.TargetDomainName — domain of the login account
  • event_data.TargetUserName — user name of the login account
  • hostip_host — host name

Use Case with Data Points

Remote desktop logins are monitored, and if a local source IP address is seen, an alert is triggered. A sample Interflow includes the source IP address (hostip) and host name (hostip_host).

Analytics

N

RDP Suspicious Logon Attempt

An authenticated user who is not allowed to log on remotely attempted to connect through RDP. Check with the user.

XDR Kill Chain

  • Kill Chain Stage: Propagation

  • Tactic: [Internal] Credential Access (TA0006 )

  • Technique: Brute Force (T1110 )

  • Tags: [Internal; RDP]

Event Name

The xdr_event.name for this alert type in the Interflow data is rdp_suspicious_logon_attempt.

Severity

75

Key Fields and Relevant Data Points

  • hostip — host IP address of the RDP server  
  • hostip_host — host name
  • event_data.AccountDomain — account domain of the user who attempts to connect
  • event_data.AccountName — account name of the user who attempts to connect
  • event_data.ClientAddress — IP address of the user who attempts to connect

Use Case with Data Points

Windows remote desktop logins are monitored, and if a user who is not allowed to remotely log in tries to log in with RDP, an alert is triggered. A sample Interflow includes the source IP address (hostip) and host name (hostip_host).

Analytics

N

Recently Registered Domains

A DNS request was observed for a site that was registered less than 90 days ago. Check the domain. If suspicious, notify users.

XDR Kill Chain

  • Kill Chain Stage: Initial Attempts

  • Tactic: [External] XDR NBA (XTA0002)

  • Technique: XDR New Domain (XT2008)

  • Tags: [External; Network Traffic Analysis]

Event Name

The xdr_event.name for this alert type in the Interflow data is new_registered_domain.

Severity

50

Key Fields and Relevant Data Points

  • metadata.request.effective_tld — top-level domain name in the request  
  • srcip_host — host name of corresponding source IP address
  • dstip_host — host name of corresponding destination IP address
  • metadata.response.domain_creation — domain creation time
  • metadata.response.effective_tld — top-level domain name in the response
  • metadata.response.resolved_ips — list of resolved IP addresses
  • actual — number of visits to the domain in the period

Use Case with Data Points

If a domain has been registered within the last 90 days, an alert is triggered. A sample Interflow includes the domain name (metadata.request.effective_tld), source host (srcip_host), destination host (dstip_host), and domain creation time (metadata.response.domain_creation).

Analytics

N

Scanner Reputation Anomaly

An anomalously large amount of connections were observed from an IP address with a reputation of being a scanner. Cross-check with the IP/Port Scan Anomaly alert, and check the links and content for possible spam or phishing.

XDR Kill Chain

  • Kill Chain Stage: Initial Attempts

  • Tactic: Reconnaissance (TA0043 )

  • Technique: Active Scanning (T1595 )

  • Tags: [Network Traffic Analysis]

Event Name

The xdr_event.name for this alert type in the Interflow data is scanner_rep.

Severity

20

Key Fields and Relevant Data Points

  • srcip_host — host name of corresponding source IP address  
  • srcip_reputation — source reputation
  • srcip_geo.countryName — source country
  • actual — actual number of connections from this source in the period
  • typical — typical number of connections from this source in the period
  • dstip_host — host name of corresponding destination IP address

Use Case with Data Points

The number of connections from a source IP address (srcip_host) with a reputation as a scanner (srcip_reputation) is calculated every 5 minutes. If the number of connections (actual) is much greater than normal (typical), an alert is triggered. The Interflow includes information such as the source country (srcip_geo.countryName) and a destination (dstip_host).

Unsupervised

Y

Sensitive Windows Active Directory Attribute Modification

The Sensitive Windows Active Directory Attribute Modification rules are used to identify suspicious activity with Sensitive Windows Active Directory Attribute Modification. Any one or more of these will trigger the Sensitive Windows Active Directory Attribute Modification alert type.

Event Name

The xdr_event.name for this alert type in the Interflow data is windows_security_ad_sensitive_attribute_modification.

Key Fields and Relevant Data Points

  • event_id — Windows event ID associated with the activity 
  • hostip — host IP address 
  • hostip_host — host name
  • stellar.rule_id — Stellar Cyber rule ID

Link to Rule-Based Alert Types

Rules Contributing to Sensitive Windows Active Directory Attribute Modification Alert Type

Analytics

N

Sensitive Windows Network Share File or Folder Accessed

The Sensitive Windows Network Share File or Folder Accessed rules are used to identify suspicious activity with Windows Network Share File or Folder Access. Any one or more of these will trigger the Sensitive Windows Network Share File or Folder Accessed alert type.

Event Name

The xdr_event.name for this alert type in the Interflow data is windows_security_sensitive_networkshare.

Key Fields and Relevant Data Points

  • event_id — Windows event ID associated with the activity 
  • hostip — host IP address 
  • hostip_host — host name
  • stellar.rule_id — Stellar Cyber rule ID

Link to Rule-Based Alert Types

Rules Contributing to Sensitive Windows Network Share File or Folder Accessed Alert Type

Analytics

N

Sensor Status Anomaly

The sensor has changed its status from "connected" to "disconnected".

XDR Kill Chain

  • Kill Chain Stage: Initial Attempts

  • Tactic: XDR SBA (XTA0003)

  • Technique: XDR Status Anomaly (XT3002)

  • Tags: [Network Traffic Analysis]

Event Name

The xdr_event.name for this alert type in the Interflow data is ade_outbytes_anomaly_flip.

Severity

10

Key Fields and Relevant Data Points

  • engid — sensor ID  
  • engid_name — sensor name

Use Case with Data Points

For each sensor, its connection status is checked periodically, if the status changes from “connected“ to “disconnected“, the anomaly is triggered. A sample Interflow includes the sensor ID (engid) and sensor name (engid_name).

Unsupervised

Y

SMB Impacket Lateralization

The execution of wmiexec, dcomexec, atexec, smbexec or PSExec from the Impacket framework was observed. Check the source host. If malicious, consider blocking the host.

XDR Kill Chain

  • Kill Chain Stage: Persistent Foothold

  • Tactic: Execution (TA0002 )

  • Technique: Windows Management Instrumentation (T1047 )

  • Tags: []

Event Name

The xdr_event.name for this alert type in the Interflow data is smb_impacket_lateralization.

Severity

80

Key Fields and Relevant Data Points

  • srcip — source IP address  
  • hostip — host IP address
  • hostip_host — host name
  • event_data.CommandLine — command line of the command that was executed
  • event_data.ParentCommandLine — command line of the parent process

Use Case with Data Points

If a Windows host (srcip) executes a command (wmiexec, dcomexec, atexec, smbexec, or PSExec) from the Impacket framework, an alert is triggered. A sample Interflow includes the source IP address (srcip), source host (srcip_host), and the command executed (event_data.CommandLine).

Analytics

N

SMB Specific Service Installation

A specific service installation used by the Impacket tool or Metasploit was observed. Check the source host. If malicious, consider blocking the host.

XDR Kill Chain

  • Kill Chain Stage: Persistent Foothold

  • Tactic: Execution (TA0002 )

  • Technique: System Services (T1569 )

  • Tags: []

Event Name

The xdr_event.name for this alert type in the Interflow data is smb_hack_smbexec.

Severity

80

Key Fields and Relevant Data Points

  • srcip — source IP address 
  • event_data.ServiceName — name of the service installed 
  • hostip — host IP address
  • hostip_host — host name

Use Case with Data Points

If a Windows host (srcip) installs a specific service installation that is used by the smbexec.py tool, an alert is triggered. A sample Interflow includes the source IP address (srcip), source host (srcip_host), and the service installed (event_data.ServiceName).

Analytics

N

SMB Suspicious Copy

A suspicious copy command from a remote C$ or ADMIN$ share was observed. Check the source host. If malicious, consider blocking the host.

XDR Kill Chain

  • Kill Chain Stage: Exploration

  • Tactic: Collection (TA0009 )

  • Technique: Data from Network Shared Drive (T1039 )

  • Tags: []

Event Name

The xdr_event.name for this alert type in the Interflow data is smb_suspicious_copy.

Severity

75

Key Fields and Relevant Data Points

  • srcip — source IP address  
  • hostip — host IP address
  • hostip_host — host name
  • event_data.CommandLine — command line of the copy command

Use Case with Data Points

If a Windows host (srcip) uses the copy command to copy files from a remote C$ or ADMIN$ share, an alert is triggered. A sample Interflow includes the source IP address (srcip), source host (srcip_host), and the command executed (event_data.CommandLine).

Analytics

N

Steal or Forge Kerberos Tickets

The Steal or Forge Kerberos Tickets rules are used to identify suspicious activity to steal or forge Kerberos tickets. Any one or more of these will trigger the Steal or Forge Kerberos Tickets alert type.

Event Name

The xdr_event.name for this alert type in the Interflow data is windows_security_steal_or_forge_kerberos_tickets.

Key Fields and Relevant Data Points

  • hostip — host IP address 
  • hostip_host — host name
  • wineventlog_user — Windows user who executed the script
  • event_data.ScriptBlockText — Powershell script block text
  • event_id — Windows event ID associated with the activity
  • stellar.rule_id — Stellar Cyber rule ID

Link to Rule-Based Alert Types

Rules Contributing to Steal or Forge Kerberos Tickets Alert Type

Analytics

N

Suspicious Access Attempt to Windows Object

The Suspicious Access Attempt to Windows Object rules are used to identify suspicious activity with Access Attempt to Windows Objects. Any one or more of these will trigger the Suspicious Access Attempt to Windows Object alert type.

Event Name

The xdr_event.name for this alert type in the Interflow data is windows_security_object_access_suspicious_attempt.

Key Fields and Relevant Data Points

  • event_id — Windows event ID associated with the activity 
  • hostip — host IP address 
  • hostip_host — host name
  • stellar.rule_id — Stellar Cyber rule ID

Link to Rule-Based Alert Types

Rules Contributing to Suspicious Access Attempt to Windows Object Alert Type

Analytics

N

Suspicious Activity Related to Security-Enabled Group

The Suspicious Activity Related to Security-Enabled Group rules are used to identify suspicious activity related to security-enabled groups. Any one or more of these will trigger the Suspicious Activity Related to Security-Enabled Group alert types.

Event Name

The xdr_event.name for this alert type in the Interflow data is windows_security_suspicious_activity_related_to_security_enabled_group.

Key Fields and Relevant Data Points

  • hostip — host IP address 
  • event_id — Windows event ID associated with the activity 
  • hostip_host — host name
  • event_data.SubjectUserName — subject user name associated with the activity
  • event_data.SubjectUserSid — subject user SID associated with the activity
  • stellar.rule_id — Stellar Cyber rule ID

Link to Rule-Based Alert Types

Rules Contributing to Suspicious Activity Related to Security-Enabled Group Alert Type

Analytics

N

Suspicious AWS Bucket Enumeration

The Suspicious AWS Bucket Enumeration rules are used to identify suspicious activity related to AWS Bucket Enumeration. Any one or more of these will trigger the AWS Bucket Enumeration alert type.

Event Name

The xdr_event.name for this alert type in the Interflow data is aws_suspicious_bucket_enumeration.

Key Fields and Relevant Data Points

  • eventSource — source of event 
  • eventName — name of event 
  • eventType — type of event
  • userIdentity.accountId — key ID for the account involved in the event
  • userIdentity.userName — user name of the account involved in the event
  • userIdentity.type — type of account involved in the event
  • stellar.rule_id — Stellar Cyber rule ID

Link to Rule-Based Alert Types

Rules Contributing to Suspicious AWS Bucket Enumeration Alert Type

Analytics

N

Suspicious AWS EBS Activity

The Suspicious AWS EBS Activity rules are used to identify suspicious AWS Elastic Block Store (EBS) activity. Any one or more of these will trigger the Suspicious AWS EBS Activity alert type.

Event Name

The xdr_event.name for this alert type in the Interflow data is aws_suspicious_ebs_activity.

Key Fields and Relevant Data Points

  • eventSource — source of event 
  • eventName — name of event 
  • eventType — type of event
  • userIdentity.accountId — key ID for the account involved in the event
  • userIdentity.userName — user name of the account involved in the event
  • userIdentity.type — type of account involved in the event
  • stellar.rule_id — Stellar Cyber rule ID

Link to Rule-Based Alert Types

Rules Contributing to Suspicious AWS EBS Activity Alert Type

Analytics

N

Suspicious AWS EC2 Activity

The Suspicious AWS EC2 Activity rules are used to identify suspicious activity within AWS EC2 logs. Any one or more of these will trigger the Suspicious AWS EC2 Activity alert type.

Event Name

The xdr_event.name for this alert type in the Interflow data is aws_suspicious_ec2_activity.

Key Fields and Relevant Data Points

  • eventSource — source of event 
  • eventName — name of event 
  • eventType — type of event
  • userIdentity.accountId — key ID for the account involved in the event
  • userIdentity.userName — user name of the account involved in the event
  • userIdentity.type — type of account involved in the event
  • stellar.rule_id — Stellar Cyber rule ID

Link to Rule-Based Alert Types

Rules Contributing to Suspicious AWS EC2 Activity Alert Type

Analytics

N

Suspicious AWS ELB Activity

The Suspicious AWS ELB Activity rules are used to identify suspicious activity with AWS ELB. Any one or more of these will trigger the Suspicious AWS ELB Activity alert type.

Event Name

The xdr_event.name for this alert type in the Interflow data is aws_suspicious_elb_activity.

Key Fields and Relevant Data Points

  • eventSource — source of event 
  • eventName — name of event 
  • eventType — type of event
  • userIdentity.accountId — key ID for the account involved in the event
  • userIdentity.userName — user name of the account involved in the event
  • userIdentity.type — type of account involved in the event
  • stellar.rule_id — Stellar Cyber rule ID

Link to Rule-Based Alert Types

Rules Contributing to Suspicious AWS ELB Activity Alert Type

Analytics

N

Suspicious AWS IAM Activity

The Suspicious AWS IAM Activity rules are used to identify suspicious activity within AWS IAM logs. Any one or more of these will trigger the Suspicious AWS IAM Activity alert type.

Event Name

The xdr_event.name for this alert type in the Interflow data is aws_suspicious_iam_activity.

Key Fields and Relevant Data Points

  • eventSource — source of event 
  • eventName — name of event 
  • eventType — type of event
  • userIdentity.accountId — key ID for the account involved in the event
  • userIdentity.userName — user name of the account involved in the event
  • userIdentity.type — type of account involved in the event
  • stellar.rule_id — Stellar Cyber rule ID

Link to Rule-Based Alert Types

Rules Contributing to Suspicious AWS IAM Activity Alert Type

Analytics

N

Suspicious AWS RDS Event

The Suspicious AWS RDS Event rules are used to identify suspicious activity related to AWS RDS Event. Any one or more of these will trigger the Suspicious AWS RDS Event alert type.

Event Name

The xdr_event.name for this alert type in the Interflow data is aws_suspicious_rds_event.

Key Fields and Relevant Data Points

  • eventSource — source of event 
  • eventName — name of event 
  • eventType — type of event
  • userIdentity.accountId — key ID for the account involved in the event
  • userIdentity.userName — user name of the account involved in the event
  • userIdentity.type — type of account involved in the event
  • stellar.rule_id — Stellar Cyber rule ID

Link to Rule-Based Alert Types

Rules Contributing to Suspicious AWS RDS Event Alert Type

Analytics

N

Suspicious AWS Root Account Activity

The Suspicious AWS Root Account Activity rules are used to identify suspicious activity with AWS Root Account. Any one or more of these will trigger the Suspicious AWS Root Account Activity alert type.

Event Name

The xdr_event.name for this alert type in the Interflow data is aws_suspicious_root_account_activity.

Key Fields and Relevant Data Points

  • eventSource — source of event 
  • eventName — name of event 
  • eventType — type of event
  • userIdentity.accountId — key ID for the account involved in the event
  • userIdentity.userName — user name of the account involved in the event
  • userIdentity.type — type of account involved in the event
  • stellar.rule_id — Stellar Cyber rule ID

Link to Rule-Based Alert Types

Rules Contributing to Suspicious AWS Root Account Activity Alert Type

Analytics

N

Suspicious AWS Route 53 Activity

The Suspicious AWS Route 53 Activity rules are used to identify suspicious activity within AWS Route 53 logs. Any one or more of these will trigger the Suspicious AWS Route 53 Activity alert type.

Event Name

The xdr_event.name for this alert type in the Interflow data is aws_suspicious_route53_activity.

Key Fields and Relevant Data Points

  • eventSource — source of event 
  • eventName — name of event 
  • eventType — type of event
  • userIdentity.accountId — key ID for the account involved in the event
  • userIdentity.userName — user name of the account involved in the event
  • userIdentity.type — type of account involved in the event
  • stellar.rule_id — Stellar Cyber rule ID

Link to Rule-Based Alert Types

Rules Contributing to Suspicious AWS Route 53 Activity Alert Type

Analytics

N

Suspicious AWS SSL Certificate Activity

The Suspicious AWS SSL Certificate Activity rules are used to identify suspicious activity with AWS SSL certificates. Any one or more of these will trigger the Suspicious AWS SSL Certificate alert type.

Event Name

The xdr_event.name for this alert type in the Interflow data is aws_suspicious_ssl_certificate_activity.

Key Fields and Relevant Data Points

  • eventSource — source of event 
  • eventName — name of event 
  • eventType — type of event
  • userIdentity.accountId — key ID for the account involved in the event
  • userIdentity.userName — user name of the account involved in the event
  • userIdentity.type — type of account involved in the event
  • stellar.rule_id — Stellar Cyber rule ID

Link to Rule-Based Alert Types

Rules Contributing to Suspicious AWS SSL Certificate Activity Alert Type

Analytics

N

Suspicious AWS VPC Flow Logs Modification

The Suspicious AWS VPC Flow Logs Modification rules are used to identify suspicious modification of AWS VPC Flow logs. Any one or more of these will trigger the Suspicious AWS VPC Flow Logs Modification alert type.

Event Name

The xdr_event.name for this alert type in the Interflow data is aws_suspicious_vpc_flow_logs_modification.

Key Fields and Relevant Data Points

  • eventSource — source of event 
  • eventName — name of event 
  • eventType — type of event
  • userIdentity.accountId — key ID for the account involved in the event
  • userIdentity.userName — user name of the account involved in the event
  • userIdentity.type — type of account involved in the event
  • stellar.rule_id — Stellar Cyber rule ID

Link to Rule-Based Alert Types

Rules Contributing to Suspicious AWS VPC Flow Logs Modification Alert Type

Analytics

N

Suspicious AWS VPC Mirror Session

The Suspicious AWS VPC Mirror Session rules are used to identify suspicious AWS VPC mirror session activity. Any one or more of these will trigger the Suspicious AWS VPC Mirror Session alert type.

Event Name

The xdr_event.name for this alert type in the Interflow data is aws_suspicious_vpc_mirror_session.

Key Fields and Relevant Data Points

  • eventSource — source of event 
  • eventName — name of event 
  • eventType — type of event
  • userIdentity.accountId — key ID for the account involved in the event
  • userIdentity.userName — user name of the account involved in the event
  • userIdentity.type — type of account involved in the event
  • stellar.rule_id — Stellar Cyber rule ID

Link to Rule-Based Alert Types

Rules Contributing to Suspicious AWS VPC Mirror Session Alert Type

Analytics

N

Suspicious Connection to Another Process

The Suspicious Connection to Another Process rules are used to identify suspicious activity with Suspicious Connection to Another Process. Any one or more of these will trigger the Suspicious Connection to Another Process alert types.

Event Name

The xdr_event.name for this alert type in the Interflow data is windows_security_suspicious_connection_process.

Key Fields and Relevant Data Points

  • event_id — Windows event ID associated with the activity 
  • hostip — host IP address 
  • hostip_host — host name
  • stellar.rule_id — Stellar Cyber rule ID

Link to Rule-Based Alert Types

Rules Contributing to Suspicious Connection to Another Process Alert Type

Analytics

N

Suspicious Handle Request to Sensitive Object

The Suspicious Handle Request to Sensitive Object rules are used to identify suspicious activity with Handle Requests to Sensitive Objects. Any one or more of these will trigger the Suspicious Handle Request to Sensitive Object alert type.

Event Name

The xdr_event.name for this alert type in the Interflow data is windows_security_suspicious_handle_request.

Key Fields and Relevant Data Points

  • event_id — Windows event ID associated with the activity 
  • hostip — host IP address 
  • hostip_host — host name
  • stellar.rule_id — Stellar Cyber rule ID

Link to Rule-Based Alert Types

Rules Contributing to Suspicious Handle Request to Sensitive Object Alert Type

Analytics

N

Suspicious LSASS Process Access

The Suspicious LSASS Process Access rules are used to identify suspicious process access to or from the Local Security Authority Subsystem Service (LSASS). Any one or more of these will trigger the Suspicious LSASS Process Access alert type.

Event Name

The xdr_event.name for this alert type in the Interflow data is suspicious_process_access_lsass.

Key Fields and Relevant Data Points

  • hostip — host IP address 
  • hostip_host — host name
  • event_data.SourceImage — source image path associated with the activity 
  • event_data.TargetImage — target image path associated with the activity 
  • wineventlog_user — user associated with the activity
  • stellar.rule_id — Stellar Cyber rule ID

Link to Rule-Based Alert Types

Rules Contributing to Suspicious LSASS Process Access Alert Type

Analytics

N

Suspicious Modification of AWS CloudTrail Logs

The Suspicious Modification of AWS CloudTrail Logs rules are used to identify suspicious activity within AWS Cloudtrail logs. Any one or more of these will trigger the Suspicious Modification of AWS CloudTrail Logs alert type.

Event Name

The xdr_event.name for this alert type in the Interflow data is aws_suspicious_cloudtrail_logs_modification.

Key Fields and Relevant Data Points

  • eventSource — source of event 
  • eventName — name of event 
  • eventType — type of event
  • userIdentity.accountId — key ID for the account involved in the event
  • userIdentity.userName — user name of the account involved in the event
  • userIdentity.type — type of account involved in the event
  • stellar.rule_id — Stellar Cyber rule ID

Link to Rule-Based Alert Types

Rules Contributing to Suspicious Modification of AWS CloudTrail Logs Alert Type

Analytics

N

Suspicious Modification of AWS Route Table

The Suspicious Modification of AWS Route Table rules are used to identify suspicious activity related to modification of AWS Route Table. Any one or more of these will trigger the Suspicious Modification of AWS Route Table alert type.

Event Name

The xdr_event.name for this alert type in the Interflow data is aws_suspicious_modification_of_route_table.

Key Fields and Relevant Data Points

  • eventSource — source of event 
  • eventName — name of event 
  • eventType — type of event
  • userIdentity.accountId — key ID for the account involved in the event
  • userIdentity.userName — user name of the account involved in the event
  • userIdentity.type — type of account involved in the event
  • stellar.rule_id — Stellar Cyber rule ID

Link to Rule-Based Alert Types

Rules Contributing to Suspicious Modification of AWS Route Table Alert Type

Analytics

N

Suspicious Modification of S3 Bucket

The Suspicious Modification of S3 Bucket rules are used to identify suspicious activity within S3 Bucket logs. Any one or more of these will trigger the Suspicious Modification of S3 Bucket alert type.

Event Name

The xdr_event.name for this alert type in the Interflow data is aws_suspicious_modification_of_s3_bucket.

Key Fields and Relevant Data Points

  • eventSource — source of event 
  • eventName — name of event 
  • eventType — type of event
  • userIdentity.accountId — key ID for the account involved in the event
  • userIdentity.userName — user name of the account involved in the event
  • userIdentity.type — type of account involved in the event
  • stellar.rule_id — Stellar Cyber rule ID

Link to Rule-Based Alert Types

Rules Contributing to Suspicious Modification of S3 Bucket Alert Type

Analytics

N

Suspicious Powershell Script

The Suspicious Powershell Script rules are used to identify suspicious activity relating to PowerShell scripts. Any one or more of these will trigger the Suspicious PowerShell Script alert types.

Event Name

The xdr_event.name for this alert type in the Interflow data is suspicious_powershell_script.

Key Fields and Relevant Data Points

  • hostip — host IP address 
  • hostip_host — host name
  • wineventlog_user — Windows user who executed the script
  • event_data.ScriptBlockText — Powershell script block text
  • stellar.rule_id — Stellar Cyber rule ID

Link to Rule-Based Alert Types

Rules Contributing to Suspicious Powershell Script Alert Type

Analytics

N

Suspicious Process Creation Commandline

The Suspicious Process Creation Commandline rules are used to identify suspicious activity relating to command-line process creation. Any one or more of these will trigger the Suspicious Process Creation Commandline alert types.

Event Name

The xdr_event.name for this alert type in the Interflow data is suspicious_commandline.

Key Fields and Relevant Data Points

  • hostip — host IP address 
  • event_data.CommandLine — process creation command line 
  • hostip_host — host name
  • wineventlog_user — Windows user who executed the command
  • stellar.rule_id — Stellar Cyber rule ID

Link to Rule-Based Alert Types

Rules Contributing to Suspicious Process Creation Commandline Alert Type

Analytics

N

Suspicious Windows Active Directory Operation

The Suspicious Windows Active Directory Operation rules are used to identify suspicious activity with Windows Active Directory Operation. Any one or more of these will trigger the Suspicious Windows Active Directory Operation alert type.

Event Name

The xdr_event.name for this alert type in the Interflow data is windows_security_ad_suspicious_operation.

Key Fields and Relevant Data Points

  • event_id — Windows event ID associated with the activity 
  • hostip — host IP address 
  • hostip_host — host name
  • stellar.rule_id — Stellar Cyber rule ID

Link to Rule-Based Alert Types

Rules Contributing to Suspicious Windows Active Directory Operation Alert Type

Analytics

N

Suspicious Windows Logon Event

The Suspicious Windows Logon Event rules are used to identify suspicious activity with Windows Logons. Any one or more of these will trigger the Suspicious Windows Logon alert types.

Event Name

The xdr_event.name for this alert type in the Interflow data is windows_security_suspicious_logon_event.

Key Fields and Relevant Data Points

  • event_id — Windows event ID associated with the activity 
  • hostip — host IP address 
  • hostip_host — host name
  • stellar.rule_id — Stellar Cyber rule ID

Link to Rule-Based Alert Types

Rules Contributing to Suspicious Windows Logon Event Alert Type

Analytics

N

Suspicious Windows Network Connection

The Suspicious Windows Network Connection rules are used to identify suspicious Windows network connection activities. Any one or more of these will trigger the Suspicious Windows Network Connection alert type.

Event Name

The xdr_event.name for this alert type in the Interflow data is suspicious_windows_network_connection.

Key Fields and Relevant Data Points

  • hostip — host IP address 
  • hostip_host — host name
  • event_data.Image — process associated with the activity 
  • wineventlog_user — user associated with the activity
  • stellar.rule_id — Stellar Cyber rule ID

Link to Rule-Based Alert Types

Rules Contributing to Suspicious Windows Network Connection Alert Type

Analytics

N

Suspicious Windows Process Creation

The Suspicious Windows Process Creation rules are used to identify suspicious activity associated with process creation. Any one or more of these will trigger the Suspicious Process Creation alert type.

Event Name

The xdr_event.name for this alert type in the Interflow data is windows_suspicious_process_creation.

Key Fields and Relevant Data Points

  • hostip — host IP address 
  • process_name — process associated with the activity 
  • hostip_host — host name
  • wineventlog_user — Windows user associated with the activity
  • stellar.rule_id — Stellar Cyber rule ID

Link to Rule-Based Alert Types

Rules Contributing to Windows Suspicious Process Creation Alert Type

Analytics

N

Suspicious Windows Registry Event: Impact

The Suspicious Windows Registry Event: Impact rules are used to identify suspicious Windows registry events usually in the impact stage. Any one or more of these will trigger the Suspicious Windows Registry Event: Impact alert type.

Event Name

The xdr_event.name for this alert type in the Interflow data is suspicious_windows_registry_event_impact.

Key Fields and Relevant Data Points

  • hostip — host IP address 
  • hostip_host — host name
  • event_data.Image — process associated with the activity
  • event_data.TargetObject — target registry 
  • event_data.Details — value set to the registry
  • wineventlog_user — user associated with the activity
  • stellar.rule_id — Stellar Cyber rule ID

Link to Rule-Based Alert Types

Rules Contributing to Suspicious Windows Registry Event: Impact Alert Type

Analytics

N

Suspicious Windows Registry Event: Persistence

The Suspicious Windows Registry Event: Persistence rules are used to identify suspicious Windows registry events usually in the persistence stage. Any one or more of these will trigger the Suspicious Windows Registry Event: Persistence alert type.

Event Name

The xdr_event.name for this alert type in the Interflow data is suspicious_windows_registry_event_persistence.

Key Fields and Relevant Data Points

  • hostip — host IP address 
  • hostip_host — host name
  • event_data.Image — process associated with the activity
  • event_data.TargetObject — target registry 
  • event_data.Details — value set to the registry
  • wineventlog_user — user associated with the activity
  • stellar.rule_id — Stellar Cyber rule ID

Link to Rule-Based Alert Types

Rules Contributing to Suspicious Windows Registry Event: Persistence Alert Type

Analytics

N

Suspicious Windows Service Installation

The Suspicious Windows Service Installation rules are used to identify suspicious activity with service installation. Any one or more of these will trigger the Suspicious Windows Service Installation alert type.

Event Name

The xdr_event.name for this alert type in the Interflow data is windows_security_suspicious_service_installation.

Key Fields and Relevant Data Points

  • event_id — Windows event ID associated with the activity 
  • hostip — host IP address 
  • hostip_host — host name
  • stellar.rule_id — Stellar Cyber rule ID

Link to Rule-Based Alert Types

Rules Contributing to Suspicious Windows Service Installation Alert Type

Analytics

N

Unapproved Asset Activity

Activity of an asset has been marked as unapproved in one of the Investigate | Asset Activity tabs. Unapproved assets generate one alert per day until their approval status is changed with either the Approve or Ignore button in the Asset Activity tabs.

XDR Kill Chain

  • Kill Chain Stage: Exploration

  • Tactic: [Internal] XDR NBA (XTA0002)

  • Technique: XDR Unapproved Asset Activity (XT2013)

  • Tags: [Network Traffic Analysis]

Event Name

The xdr_event.name for this alert type in the Interflow data is asset_violation.

Severity

50

Key Fields and Relevant Data Points

  • asset_id — ID of a specific asset  
  • vendor — vendor of this asset

Use Case with Data Points

If an analyst marks an asset as unapproved in the Asset Activity tabs, a daily alert is triggered until the asset is either manually approved or ignored.

Analytics

N

Uncommon Application Anomaly

Private (internal assets) to public (Internet) traffic has revealed an application that has never been seen before (or been seen very rarely). Investigate that application and ensure that it is benign.

XDR Kill Chain

  • Kill Chain Stage: Initial Attempts

  • Tactic: [External] XDR NBA (XTA0002)

  • Technique: XDR App Anomaly (XT2003)

  • Tags: [External; Traffic Analysis]

Event Name

The xdr_event.name for this alert type in the Interflow data is network_uncommon_app.

Severity

20

Key Fields and Relevant Data Points

  • appid — application ID  
  • appid_name — application name
  • days_silent — number of days since this application was last seen
  • srcip_host — host name of corresponding source IP address
  • srcip_reputation — source reputation
  • srcip_geo.countryName — source country
  • dstip_host — host name of corresponding destination IP address
  • dstip_reputation — destination reputation
  • dstip_geo.countryName — destination country

Use Case with Data Points

If an application (appid) has never been observed by Stellar Cyber or been seen very rarely (days_silent), an alert is triggered. The Interflow includes the internal assets (srcip_host), source reputation (srcip_reputation), and source country (srcip_geo.countryName), and the destination host (dstip_host), destination reputation (dstip_reputation), and destination country (dstip_geo.countryName).

Unsupervised

Y

Uncommon Process Anomaly

An asset launched a process that has never been seen before (or has very rarely been seen). This could indicate a malware attack.

XDR Kill Chain

  • Kill Chain Stage: Persistent Foothold

  • Tactic: XDR EBA (XTA0001)

  • Technique: XDR Process Anomaly (XT1001)

  • Tags: []

Event Name

The xdr_event.name for this alert type in the Interflow data is network_uncommon_process.

Severity

30

Key Fields and Relevant Data Points

  • hostip — IP address of the host running the process
  • hostip_host — host name
  • process_name — name of the process  
  • wineventlog_user — user that created the process
  • days_silent — number of days since this process was last seen

Use Case with Data Points

If a process (process_name) has never been observed by Stellar Cyber or been seen very rarely (days_silent), an alert is triggered. The Interflow includes the user (process_user) and host (srcip) that executed the process.

Unsupervised

Y

User Asset Access Anomaly

A user who typically uses a small, consistent number of assets logged in to a new asset. Investigate the asset and user to see if this was expected.

XDR Kill Chain

  • Kill Chain Stage: Propagation

  • Tactic: [Internal] XDR UBA (XTA0004)

  • Technique: XDR Asset Anomaly (XT4004)

  • Tags: [Internal; User Behavior Analytics]

Event Name

The xdr_event.name for this alert type in the Interflow data is user_asset_access.

Severity

30

Key Fields and Relevant Data Points

  • srcip_usersid — source user ID  
  • srcip_host — host name of corresponding source IP address 
  • dstip_host — host name of corresponding destination IP address
  • srcip_username — source user name
  • stability — score measuring the time since the last new asset was accessed
  • days_stable — time since the last new asset was accessed
  • diversity — score measuring the number of assets that the user accessed
  • child_count — number of assets that the user accessed

Use Case with Data Points

Users (srcip_usersid and srcip_username) with a small number of assets (diversity, child_count) who also have not used a new asset (srcip_host) for a long time (stability, days_stable) are examined. If a new asset appears on a host (srcip_host) with this user, an alert is triggered.

The user is identified with the scrip_userid and scrip_username fields. The asset is identified with the scrip_host field. Active Directory, which is identified from the dstip_host field, provides the relationship between the user and the asset. Stability is identified with the stability field and diversity is identified with the diversity field.

Unsupervised

Y

User Login Location Anomaly

A login to a user account occurred from a source IP address that is anomalously distant from the nearest location typically observed for logins to that user account.

This alert type has a relatively long detection delay of up to 40 minutes because it waits for login events from high latency data sources and is sensitive to the event order of user logins.

XDR Kill Chain

  • Kill Chain Stage: Initial Attempts

  • Tactic: [External] XDR UBA (XTA0004)

  • Technique: XDR Location Anomaly (XT2001)

  • Tags: [External; User Behavior Analytics]

Event Name

The xdr_event.name for this alert type in the Interflow data is user_login_region.

Severity

50

Key Fields and Relevant Data Points

  • srcip_usersid — key ID for the source user 
  • distance_deviation — deviation in distance between two login locations (miles)
  • srcip_host — host name of corresponding source IP address
  • srcip_reputation — source reputation
  • srcip_geo.countryName — source country name
  • srcip_geo.region — source region name
  • srcip_geo.city — source city name
  • dstip_host — host name of corresponding destination IP address
  • login_type — type of login

Use Case with Data Points

Successful login events for certain login types (login_type) of a user (srcip_usersid) from a source host (srcip_host) and country location (srcip_geo.countryName are examined. If the detected login location is too far away (distance_deviation in miles) from that user's typical locations, an alert is triggered. The source host's reputation (srcip_reputation) is also checked. Map views of the Interflow include data points for the closest typical login locations for the user.

Unsupervised

Y

User Process Usage Anomaly

A user who typically executes a small, consistent number of processes suddenly executed a new process. Investigate the process, to see if it is benign. Check with the user to see if this process was expected.

XDR Kill Chain

  • Kill Chain Stage: Persistent Foothold

  • Tactic: XDR EBA (XTA0001)

  • Technique: XDR Process Anomaly (XT1001)

  • Tags: [User Behavior Analytics]

Event Name

The xdr_event.name for this alert type in the Interflow data is user_uncommon_process.

Severity

10

Key Fields and Relevant Data Points

  • srcip_usersid — non-Windows source user ID  

    or

  • user.identifier — Windows source user ID  

    The key field for this alert type can be either srcip_usersid or user.identifier, depending on the data feed.

  • process_name — name of the process  
  • hostip — IP address of the host
  • hostip_host — host name
  • srcip_username — source user name
  • wineventlog_user.name — source user name (Windows)
  • user.name — source user name (Windows)
  • stability — score measuring the time since the last new process was executed
  • days_stable — time since the last new process was executed
  • diversity — score measuring the number of processes that the user executed
  • child_count — number of processes that the user executed

Use Case with Data Points

Looks for a user (srcip_usersid or user.identifier and a srcip_username) with a small number of processes (diversity, child_count) who also has not used a new process for a long time (stability, days_stable). If a new process (process_name) appears on a host (srcip_host) with this user and connects to another host (dstip_host), an alert is triggered.

The user is identified with the scrip_userid or user.identifier and scrip_username fields. The process is identified with the process_name field. The host on which the user is running the process is identified with the srcip_host field. The destination of the traffic generated by the process is identified with the dstip_host field. Stability is identified with the stability field, and diversity is identified with the diversity field.

Unsupervised

Y

Volume Shadow Copy Deletion via VssAdmin

The vssadmin.exe utility was used to delete the Shadow Copy on an endpoint. Ransomware and other malware do this to prevent system recovery. Check with the user.

XDR Kill Chain

  • Kill Chain Stage: Exfiltration & Impact

  • Tactic: Impact (TA0040 )

  • Technique: Inhibit System Recovery (T1490 )

  • Tags: [Malware; Ransomware]

Event Name

The xdr_event.name for this alert type in the Interflow data is ransomware_volume_shadow_copy_deletion_via_vssadminedit.

Severity

80

Key Fields and Relevant Data Points

  • hostip — IP address of the host where the Shadow Copy was deleted  
  • hostip_host — host name
  • process_name — name of the executed process
  • event_data.CommandLine — command that was executed to delete the Shadow Copy

Use Case with Data Points

If vssadmin.exe is used to delete the Shadow Copy on an endpoint, an alert is triggered. The Interflow ibncludes the host IP address (hostip), process name (process_name), and command line (event_data.CommandLine).

Analytics

N

Volume Shadow Copy Deletion via WMIC

The wmic.exe utility was used to delete the Shadow Copy on an endpoint. Ransomware and other malware do this to prevent system recovery. Check with the user.

XDR Kill Chain

  • Kill Chain Stage: Exfiltration & Impact

  • Tactic: Impact (TA0040 )

  • Technique: Inhibit System Recovery (T1490 )

  • Tags: [Malware; Ransomware]

Event Name

The xdr_event.name for this alert type in the Interflow data is ransomware_volume_shadow_copy_deletion_via_wmicredit.

Severity

80

Key Fields and Relevant Data Points

  • hostip — IP address of the host where the Shadow Copy was deleted  
  • hostip_host — host name
  • process_name — name of the executed process
  • event_data.CommandLine — command that was executed to delete the Shadow Copy

Use Case with Data Points

If wmic.exe is used to delete the Shadow Copy on an endpoint, an alert is triggered. The Interflow includes the host IP address (hostip), process name (process_name), and command line (event_data.CommandLine).

Analytics

N

WAF Internal Attacker Anomaly

Internal web requests from a private IP address have been blocked/alerted by the Web Application Firewall (WAF). Investigate the source requester and ensure they are not compromised.

XDR Kill Chain

  • Kill Chain Stage: Exploration

  • Tactic: [Internal] XDR NBA (XTA0002)

  • Technique: XDR WAF Anomaly (XT2009)

  • Tags: [Internal]

Event Name

The xdr_event.name for this alert type in the Interflow data is waf_internal_attacker.

Severity

60

Key Fields and Relevant Data Points

  • srcip — source IP address  
  • srcip_host — host name of corresponding source IP address
  • action — status of web requests
  • event.severity_str — severity level of web requests
  • event.uri — URI of the web request
  • event.reason — attack type (signature name)

The above fields are standardized to support a variety of WAFs. The original fields, listed below, remain in the F5 WAF Interflow record for backward compatibility.

List of F5 legacy fields Closed

F5 Field Purpose

Original Stellar Cyber
WAF Field Name

Standardized Stellar Cyber
WAF Field Name

Signature IDf5.sig_idsevent.sig_id
Signature namef5.sig_namesevent.reason
Staged signature IDf5.staged_sig_idsevent.staged_sig_id
Staged signature IDf5.staged_sig_namesevent.staged_sig_name
Violationf5.violationsevent.violations
Sub violationf5.sub_violationsevent.sub_violations
Threat campaignf5.threat_campaign_namesevent.threat_campaign_names
Request statusf5.request_statusaction
Severityf5.severityevent.severity_str
Attack typef5.attack_typethreat
Client IPsrcip

srcip
service.origin.ip

Client Portsrcport

srcport
service.origin.port

Service IPdstipdstip
service.target.ip
Service Portdstportdstport
service.target.port
Violation Detailsf5.violation_detailsevent.description
Telemetry Event Categoryf5.telemetryEventCategoryevent.telemetry_event_category
urlf5.urievent.uri
Web application namef5.web_application_nameevent.web_application_name

Use Case with Data Points

If web requests (f5.uri) from an internal IP address (srcip) to a web application (f5.web_application_name) have been blocked/alerted (f5.request_status) by the WAF, an alert is triggered. The Interflow includes the level of severity (f5.severity), the attack type (f5.attack_type), and the violation information (f5.violations), as well as signature name (f5.sig_names), staged signature name (f5.staged_sig_names), sub violation information (f5.sub_violations), and threat campaign name (f5.violation_details_xml.request-violations.violation.threat_campaign_data.threat_campaign_name), if applicable.

If web requests (event.uri) from an internal IP address ( srcip) to a web application (event.web_application_name) have been blocked/alerted (action) by the WAF, an alert is triggered. The Interflow includes the level of severity (event.severity_str), the attack type (threat), and the violation information (event.description), as well as signature name (event.reason). If applicable for the WAF type, the Interflow also includes staged signature name (event.staged_sig_id), sub violation information (event.sub_violations), and threat campaign name (event.threat_campaign.names).

Ingestion Types Supported for this Alert

  • F5 Big-IP Firewall

  • F5 Silverline WAF

  • Barracuda WAF

  • AWS CloudWatch WAF

Analytics

N

WAF Rule Violation Anomaly

Web requests have been blocked/alerted by the Web Application Firewall (WAF) due to a surge in violations or violating a rule that is rarely invoked. Investigate the blocked/alerted web requests and ensure they are benign.

Refer to Log Parser Portsfor the most current list of WAF parsers.

XDR Kill Chain

  • Kill Chain Stage: Initial Attempts

  • Tactic: [External] XDR NBA (XTA0002)

  • Technique: XDR Rule Violation (XT2004)

  • Tags: [External; Network Traffic Analysis]

Event Name

The xdr_event.name for this alert type in the Interflow data is waf_rule_violation.

Severity

50

Key Fields and Relevant Data Points

  • srcip — source IP address  
  • srcip_host — host name of corresponding source IP address
  • event.severity_str — severity level of web requests
  • event.web_application_name — web application name
  • event.uri — URI of the web request
  • event.reason — attack type (signature name)
  • event.sig_id — attack type (signature ID)
  • actual — actual number of specific WAF violations in the period
  • typical — typical number of specific WAF violations in the period

The above fields are standardized to support a variety of WAFs. The original fields, listed below, remain in the F5 WAF Interflow record for backward compatibility.

List of F5 legacy fields Closed

F5 Field Purpose

Original Stellar Cyber
WAF Field Name

Standardized Stellar Cyber
WAF Field Name

Signature IDf5.sig_idsevent.sig_id
Signature namef5.sig_namesevent.reason
Staged signature IDf5.staged_sig_idsevent.staged_sig_id
Staged signature IDf5.staged_sig_namesevent.staged_sig_name
Violationf5.violationsevent.violations
Sub violationf5.sub_violationsevent.sub_violations
Threat campaignf5.threat_campaign_namesevent.threat_campaign_names
Request statusf5.request_statusaction
Severityf5.severityevent.severity_str
Attack typef5.attack_typethreat
Client IPsrcip

srcip
service.origin.ip

Client Portsrcport

srcport
service.origin.port

Service IPdstipdstip
service.target.ip
Service Portdstportdstport
service.target.port
Violation Detailsf5.violation_detailsevent.description
Telemetry Event Categoryf5.telemetryEventCategoryevent.telemetry_event_category
urlf5.urievent.uri
Web application namef5.web_application_nameevent.web_application_name

Use Case with Data Points

If web requests (event.uri) to a web application ( event.web_application_name) have been blocked/alerted (action) by the WAF due to violating certain rules, which include the level of severity (event.severity_str), the attack type (threat), and the violation information (event.violations). If the violations (actual) surge compared to the normal number of violations in a period (typical), an alert is triggered.

Ingestion Types Supported for this Alert

  • F5 Big-IP Firewall

  • F5 Silverline WAF

  • Barracuda WAF

  • AWS CloudWatch WAF

Unsupervised

Y