Nterl0k - T1546 The curious case of CompatTelRunner and some sneaky persistence.

detections/endpoint/windows_compatibility_telemetry_suspicious_child_process.yml

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+name: Windows Compatibility Telemetry Suspicious Child Process
+id: 56fe46ca-ffef-46fe-8f0e-5cd4b7b4cc0c
+version: 1
+date: '2025-02-13'
+author: Steven Dick
+status: production
+type: TTP
+description: The following analytic detects the execution of CompatTelRunner.exe with parameters indicative of a process not part of the normal "Microsoft Compatibility Appraiser" telemetry collection. It leverages data from Endpoint Detection and Response (EDR) agents, focusing on process names, parent processes, and command-line arguments. This activity is significant because CompatTelRunner.exe and the "Microsoft Compatibility Appraiser" task always run as System and can be used to elevate privileges or establish a highly privileged persistence mechanism. If confirmed malicious, this could enable unauthorized code execution, privilege escalation, or persistent access to the compromised system.
+data_source: 
+- Windows Security Event ID 4688
+- Sysmon Event ID 1
+- CrowdStrike ProcessRollup2
+search: |-
+  |  tstats `security_content_summariesonly` values(Processes.parent_process) as Processes.parent_process, values(Processes.process) as Processes.process values(Processes.process_current_directory) AS process_current_directory, values(Processes.process_id) as Processes.process_id, values(Processes.process_guid) as Processes.process_guid, count min(_time) AS firstTime, max(_time) AS lastTime FROM datamodel=Endpoint.Processes where Processes.parent_process_name = "CompatTelRunner.exe" AND Processes.process="* -cv:*" NOT Processes.process IN ("* -m:*") BY _time span=1h Processes.user Processes.dest Processes.parent_process_name Processes.process_name
+  |`drop_dm_object_name(Processes)`
+  | `security_content_ctime(firstTime)` 
+  | `security_content_ctime(lastTime)`
+  | `windows_compatibility_telemetry_suspicious_child_process_filter`
+how_to_implement: The detection is based on data that originates from Endpoint Detection and Response (EDR) agents. These agents are designed to provide security-related telemetry from the endpoints where the agent is installed. To implement this search, you must ingest logs that contain the process GUID, process name, and parent process. Additionally, you must ingest complete command-line executions. These logs must be processed using the appropriate Splunk Technology Add-ons that are specific to the EDR product. The logs must also be mapped to the `Processes` node of the `Endpoint` data model. Use the Splunk Common Information Model (CIM) to normalize the field names and speed up the data modeling process.
+known_false_positives: None identified
+references:
+- https://attack.mitre.org/techniques/T1546/
+- https://scythe.io/threat-thursday/windows-telemetry-persistence
+- https://www.trustedsec.com/blog/abusing-windows-telemetry-for-persistence
+drilldown_searches:
+- name: View the detection results for - "$dest$"
+  search: '%original_detection_search% | search dest = "$dest$"'
+  earliest_offset: $info_min_time$
+  latest_offset: $info_max_time$
+- name: View risk events for the last 7 days for - "$dest$"
+  search: '| from datamodel Risk.All_Risk | search normalized_risk_object IN ("$dest$") starthoursago=168  | stats count min(_time) as firstTime max(_time) as lastTime values(search_name) as "Search Name" values(risk_message) as "Risk Message" values(analyticstories) as "Analytic Stories" values(annotations._all) as "Annotations" values(annotations.mitre_attack.mitre_tactic) as "ATT&CK Tactics" by normalized_risk_object | `security_content_ctime(firstTime)` | `security_content_ctime(lastTime)`'
+  earliest_offset: $info_min_time$
+  latest_offset: $info_max_time$
+- name: Investigate processes on $dest$ 
+  search: '| from datamodel Endpoint.Processes
+| search dest = "$dest$" AND process_name = "$process_name$"'
+  earliest_offset: $info_min_time$
+  latest_offset: $info_max_time$
+rba:
+  message: The process $process_name$ was launched in a suspicious manner by $parent_process_name$ on host $dest$
+  risk_objects: 
+  - field: dest
+    type: system
+    score: 70
+  threat_objects: 
+  - field: process_name
+    type: process
+tags:
+  analytic_story: 
+  - Windows Persistence Techniques
+  asset_type: Endpoint
+  mitre_attack_id: 
+  - T1546
+  - T1053.005
+  product: 
+  - Splunk Enterprise
+  - Splunk Enterprise Security
+  - Splunk Cloud
+  security_domain: endpoint
+tests:
+- name: True Positive Test
+  attack_data:
+  - data: https://media.githubusercontent.com/media/splunk/attack_data/master/datasets/attack_techniques/T1546/compattelrunner_abuse/compattelrunner_abuse.log
+    source: XmlWinEventLog:Microsoft-Windows-Sysmon/Operational
+    sourcetype: XmlWinEventLog

detections/endpoint/windows_compatibility_telemetry_tampering_through_registry.yml

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+name: Windows Compatibility Telemetry Tampering Through Registry
+id: 43834687-cc48-4878-a2fa-f76e4271791f
+version: 1
+date: '2025-02-13'
+author: Steven Dick
+status: production
+type: TTP
+description: This detection identifies suspicious modifications to the Windows Compatibility Telemetry registry settings, specifically within the "TelemetryController" registry key and "Command" registry value. It leverages data from the Endpoint.Registry data model, focusing on registry paths and values indicative of such changes. This activity is significant because CompatTelRunner.exe and the "Microsoft Compatibility Appraiser" task always run as System and can be used to elevate privileges or establish a highly privileged persistence mechanism. If confirmed malicious, this could enable unauthorized code execution, privilege escalation, or persistent access to the compromised system.
+data_source: 
+- Sysmon Event ID 13
+search: |-
+  | tstats `security_content_summariesonly` min(_time) as firstTime, max(_time) as lastTime, count FROM datamodel=Endpoint.Registry WHERE (Registry.registry_path = "*\\SOFTWARE\\Microsoft\\Windows NT\\CurrentVersion\\AppCompatFlags\\TelemetryController*" AND Registry.registry_value_name="Command" NOT Registry.registry_value_data IN ("(empty)")) BY Registry.dest Registry.user Registry.registry_path Registry.registry_key_name Registry.registry_value_name Registry.registry_value_data Registry.process_guid
+  | `drop_dm_object_name(Registry)`
+  | eval process = registry_value_data 
+  | `security_content_ctime(firstTime)` 
+  | `security_content_ctime(lastTime)`
+  | `windows_compatibility_telemetry_tampering_through_registry_filter`
+how_to_implement: The detection is based on data that originates from Endpoint Detection and Response (EDR) agents. These agents are designed to provide security-related telemetry from the endpoints where the agent is installed. To implement this search, you must ingest logs that contain the process GUID, process name, and parent process. Additionally, you must ingest complete command-line executions. These logs must be processed using the appropriate Splunk Technology Add-ons that are specific to the EDR product. The logs must also be mapped to the `Processes` node of the `Endpoint` data model. Use the Splunk Common Information Model (CIM) to normalize the field names and speed up the data modeling process.
+known_false_positives: None identified
+references:
+- https://attack.mitre.org/techniques/T1546/
+- https://scythe.io/threat-thursday/windows-telemetry-persistence
+- https://www.trustedsec.com/blog/abusing-windows-telemetry-for-persistence
+drilldown_searches:
+- name: View the detection results for - "$dest$" and "$user$"
+  search: '%original_detection_search% | search dest = "$dest$" user = "$user$"'
+  earliest_offset: $info_min_time$
+  latest_offset: $info_max_time$
+- name: View risk events for the last 7 days for - "$dest$" and "$user$"
+  search: '| from datamodel Risk.All_Risk | search normalized_risk_object IN ("$user$","$dest$") starthoursago=168  | stats count min(_time) as firstTime max(_time) as lastTime values(search_name) as "Search Name" values(risk_message) as "Risk Message" values(analyticstories) as "Analytic Stories" values(annotations._all) as "Annotations" values(annotations.mitre_attack.mitre_tactic) as "ATT&CK Tactics" by normalized_risk_object | `security_content_ctime(firstTime)` | `security_content_ctime(lastTime)`'
+  earliest_offset: $info_min_time$
+  latest_offset: $info_max_time$
+- name: Investigate registry changes on $dest$ 
+  search: '| from datamodel Endpoint.Registry
+| search registry_path = "*\\SOFTWARE\\Microsoft\\Windows NT\\CurrentVersion\\AppCompatFlags\\TelemetryController*" AND dest = "$dest$"'
+  earliest_offset: $info_min_time$
+  latest_offset: $info_max_time$
+rba:
+  message: The process $process$ was added to registry settings for the Compatibility Appraiser by $user$ on host $dest$
+  risk_objects: 
+  - field: dest
+    type: system
+    score: 70
+  - field: user
+    type: user
+    score: 70
+  threat_objects: 
+  - field: process
+    type: process
+tags:
+  analytic_story: 
+  - Windows Persistence Techniques
+  asset_type: Endpoint
+  mitre_attack_id: 
+  - T1546
+  - T1053.005
+  product: 
+  - Splunk Enterprise
+  - Splunk Enterprise Security
+  - Splunk Cloud
+  security_domain: endpoint
+tests:
+- name: True Positive Test
+  attack_data:
+  - data: https://media.githubusercontent.com/media/splunk/attack_data/master/datasets/attack_techniques/T1546/compattelrunner_abuse/compattelrunner_abuse.log
+    source: XmlWinEventLog:Microsoft-Windows-Sysmon/Operational
+    sourcetype: XmlWinEventLog