Windows Default Domain GPO Modification — Sigma Rule

Rule metadata and linked tags

Author: Swachchhanda Shrawan Poudel (Nextron Systems). Source status: experimental; severity: medium. Source dates: 2025-11-22 / not supplied.

{
  "product": "windows",
  "service": "security",
  "definition": "Enable 'Audit Directory Service Changes' in the Default Domain Controllers Policy under:\nComputer Configuration -> Policies -> Windows Settings -> Security Settings -> Advanced Audit Policy Configuration -> Audit Policies -> DS Access -> Audit Directory Service Changes (Success).\nAdditionally, proper SACL needs to be configured on the 'CN=Policies,CN=System,DC=<domain>,DC=<tld>' container in Active Directory to capture changes to Group Policy Objects.\n"
}

Pinned original Sigma rule · Detection Rule License 1.1

Source SHA-256: 913d4786fdb9cf6b05d9e1a5724064ac2d3e5e55f19674ff43a33c5f42e7c769

Detection logic

Original source YAML. Source-tag agreement is not proof of complete semantic coverage. This rule has not been compiled for a SIEM backend or validated against live telemetry here.

title: Windows Default Domain GPO Modification
id: e5ac86dd-2da1-454b-be74-05d26c769d7d
related:
    - id: dcff7e85-d01f-4eb5-badd-84e2e6be8294
      type: similar
status: experimental
description: |
    Detects modifications to Default Domain or Default Domain Controllers Group Policy Objects (GPOs).
    Adversaries may modify these default GPOs to deploy malicious configurations across the domain.
references:
    - https://www.trendmicro.com/en_us/research/25/i/unmasking-the-gentlemen-ransomware.html
    - https://adsecurity.org/?p=3377
    - https://www.pentestpartners.com/security-blog/living-off-the-land-gpo-style/
    - https://jgspiers.com/audit-group-policy-changes/
author: Swachchhanda Shrawan Poudel (Nextron Systems)
date: 2025-11-22
tags:
    - attack.privilege-escalation
    - attack.defense-impairment
    - attack.t1484.001
logsource:
    product: windows
    service: security
    definition: |
        Enable 'Audit Directory Service Changes' in the Default Domain Controllers Policy under:
        Computer Configuration -> Policies -> Windows Settings -> Security Settings -> Advanced Audit Policy Configuration -> Audit Policies -> DS Access -> Audit Directory Service Changes (Success).
        Additionally, proper SACL needs to be configured on the 'CN=Policies,CN=System,DC=<domain>,DC=<tld>' container in Active Directory to capture changes to Group Policy Objects.
detection:
    selection:
        EventID: 5136
        ObjectClass: 'groupPolicyContainer'
        ObjectDN|startswith:
            - 'CN={31B2F340-016D-11D2-945F-00C04FB984F9},CN=POLICIES,CN=SYSTEM' # Default Domain Policy
            - 'CN={6AC1786C-016F-11D2-945F-00C04FB984F9},CN=POLICIES,CN=SYSTEM' # Default Domain Controllers Policy
    condition: selection
falsepositives:
    - Legitimate modifications to Default Domain or Default Domain Controllers GPOs
level: medium

Original YAML and metadata in JSON

False positives

• Legitimate modifications to Default Domain or Default Domain Controllers GPOs

Source references

• https://www.trendmicro.com/en_us/research/25/i/unmasking-the-gentlemen-ransomware.html
• https://adsecurity.org/?p=3377
• https://www.pentestpartners.com/security-blog/living-off-the-land-gpo-style/
• https://jgspiers.com/audit-group-policy-changes/