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| 1 | +name: Windows Audit Policy Cleared via Auditpol |
| 2 | +id: f067f7cf-f41b-4a60-985e-c23e268a13cb |
| 3 | +version: 1 |
| 4 | +date: '2025-01-27' |
| 5 | +author: Nasreddine Bencherchali, Splunk |
| 6 | +status: production |
| 7 | +type: TTP |
| 8 | +description: The following analytic identifies the execution of `auditpol.exe` with the "/clear" command-line argument used to clears the audit policy. It leverages data from Endpoint Detection and Response (EDR) agents, focusing on process names and command-line executions. This activity can be significant as it indicates potential defense evasion by adversaries or Red Teams, aiming to limit data that can be leveraged for detections and audits. If confirmed malicious, this behavior could allow attackers to bypass defenses, and plan further attacks, potentially leading to full machine compromise or lateral movement. |
| 9 | +data_source: |
| 10 | +- Sysmon EventID 1 |
| 11 | +- Windows Event Log Security 4688 |
| 12 | +- CrowdStrike ProcessRollup2 |
| 13 | +search: '| tstats `security_content_summariesonly` values(Processes.process) as process min(_time) as firstTime max(_time) as lastTime from datamodel=Endpoint.Processes where `process_auditpol` Processes.process IN ("*/clear*", "*/remove*") AND NOT Processes.process IN ("*/resourceSACL*", "*/?*") by Processes.dest Processes.user Processes.parent_process Processes.parent_process_name Processes.process_name Processes.original_file_name Processes.process Processes.process_id Processes.parent_process_id | `drop_dm_object_name(Processes)` | `security_content_ctime(firstTime)` | `security_content_ctime(lastTime)` | `windows_audit_policy_cleared_via_auditpol_filter`' |
| 14 | +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 name, and process original file name. 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. |
| 15 | +known_false_positives: None identified. Attempts to disable logging should be identified and understood. |
| 16 | +references: |
| 17 | +- https://www.microsoft.com/en-us/security/blog/2021/01/20/deep-dive-into-the-solorigate-second-stage-activation-from-sunburst-to-teardrop-and-raindrop/ |
| 18 | +- https://www.cybereason.com/blog/research/prometei-botnet-exploiting-microsoft-exchange-vulnerabilities |
| 19 | +- https://attack.mitre.org/techniques/T1562/002/ |
| 20 | +- https://learn.microsoft.com/en-us/windows-server/administration/windows-commands/auditpol-clear |
| 21 | +- https://learn.microsoft.com/en-us/windows-server/administration/windows-commands/auditpol-remove |
| 22 | +drilldown_searches: |
| 23 | +- name: View the detection results for - "$user$" and "$dest$" |
| 24 | + search: '%original_detection_search% | search user = "$user$" dest = "$dest$"' |
| 25 | + earliest_offset: $info_min_time$ |
| 26 | + latest_offset: $info_max_time$ |
| 27 | +- name: View risk events for the last 7 days for - "$user$" and "$dest$" |
| 28 | + search: '| from datamodel Risk.All_Risk | search normalized_risk_object IN ("$user$", |
| 29 | + "$dest$") starthoursago=168 | stats count min(_time) as firstTime max(_time) |
| 30 | + as lastTime values(search_name) as "Search Name" values(risk_message) as "Risk |
| 31 | + Message" values(analyticstories) as "Analytic Stories" values(annotations._all) |
| 32 | + as "Annotations" values(annotations.mitre_attack.mitre_tactic) as "ATT&CK Tactics" |
| 33 | + by normalized_risk_object | `security_content_ctime(firstTime)` | `security_content_ctime(lastTime)`' |
| 34 | + earliest_offset: $info_min_time$ |
| 35 | + latest_offset: $info_max_time$ |
| 36 | +rba: |
| 37 | + message: An instance of $parent_process_name$ spawning $process_name$ was identified attempting to clear logging on endpoint $dest$ by user $user$. |
| 38 | + risk_objects: |
| 39 | + - field: user |
| 40 | + type: user |
| 41 | + score: 16 |
| 42 | + - field: dest |
| 43 | + type: system |
| 44 | + score: 16 |
| 45 | + threat_objects: |
| 46 | + - field: process_name |
| 47 | + type: process_name |
| 48 | +tags: |
| 49 | + analytic_story: |
| 50 | + - Windows Audit Policy Tampering |
| 51 | + asset_type: Endpoint |
| 52 | + mitre_attack_id: |
| 53 | + - T1562.002 |
| 54 | + product: |
| 55 | + - Splunk Enterprise |
| 56 | + - Splunk Enterprise Security |
| 57 | + - Splunk Cloud |
| 58 | + security_domain: endpoint |
| 59 | +tests: |
| 60 | +- name: True Positive Test - Sysmon |
| 61 | + attack_data: |
| 62 | + - data: |
| 63 | + https://media.githubusercontent.com/media/splunk/attack_data/master/datasets/attack_techniques/T1562.002/auditpol_tampering/auditpol_tampering_sysmon.log |
| 64 | + source: XmlWinEventLog:Microsoft-Windows-Sysmon/Operational |
| 65 | + sourcetype: XmlWinEventLog |
| 66 | +- name: True Positive Test - Security |
| 67 | + attack_data: |
| 68 | + - data: |
| 69 | + https://media.githubusercontent.com/media/splunk/attack_data/master/datasets/attack_techniques/T1562.002/auditpol_tampering/auditpol_tampering_security.log |
| 70 | + source: XmlWinEventLog:Security |
| 71 | + sourcetype: XmlWinEventLog |
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