Windows Audit Policy Excluded Category via Auditpol

name: Windows Audit Policy Excluded Category via Auditpol
id: 083708d4-d763-4ba2-87ac-105b526de81a
version: 8
creation_date: '2025-02-19'
modification_date: '2026-05-13'
author: Nasreddine Bencherchali, Splunk
status: production
type: Anomaly
description: The following analytic identifies the execution of `auditpol.exe` with the "/set" and "/exclude" command-line arguments which indicates that the user's per-user policy will cause audit to be suppressed regardless of the system 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 exclude specific users events from log data. If confirmed malicious, this behavior could allow attackers to bypass defenses, and plan further attacks, potentially leading to full machine compromise or lateral movement.
data_source:
    - Sysmon EventID 1
    - Windows Event Log Security 4688
    - CrowdStrike ProcessRollup2
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="*/set*" Processes.process="*/exclude*"
        AND
        NOT Processes.process="*/?*"
      BY Processes.action Processes.dest Processes.original_file_name
         Processes.parent_process Processes.parent_process_exec Processes.parent_process_guid
         Processes.parent_process_id Processes.parent_process_name Processes.parent_process_path
         Processes.process Processes.process_exec Processes.process_guid
         Processes.process_hash Processes.process_id Processes.process_integrity_level
         Processes.process_name Processes.process_path Processes.user
         Processes.user_id Processes.vendor_product
    | `drop_dm_object_name(Processes)`
    | `security_content_ctime(firstTime)`
    | `security_content_ctime(lastTime)`
    | `windows_audit_policy_excluded_category_via_auditpol_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 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.
known_false_positives: False positives should be rare, investigate the activity, and apply additional filters when necessary.
references:
    - 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/
    - https://www.cybereason.com/blog/research/prometei-botnet-exploiting-microsoft-exchange-vulnerabilities
    - https://attack.mitre.org/techniques/T1562/002/
    - https://learn.microsoft.com/en-us/windows-server/administration/windows-commands/auditpol-set
intermediate_findings:
    entities:
        - field: user
          type: user
          score: 20
          message: An instance of $parent_process_name$ spawning $process_name$ with CommandLine $process$ was identified attempting to exclude a specific user events on $dest$ by user $user$.
        - field: dest
          type: system
          score: 20
          message: An instance of $parent_process_name$ spawning $process_name$ with CommandLine $process$ was identified attempting to exclude a specific user events on $dest$ by user $user$.
threat_objects:
    - field: process_name
      type: process_name
analytic_story:
    - Windows Audit Policy Tampering
asset_type: Endpoint
mitre_attack_id:
    - T1685.001
product:
    - Splunk Enterprise
    - Splunk Enterprise Security
    - Splunk Cloud
category: endpoint
security_domain: endpoint