Windows Defender Exclusion Registry Key - Write Access Requested — Sigma Rule

Rule metadata and linked tags

Author: @BarryShooshooga, Nasreddine Bencherchali (Nextron Systems). Source status: test; severity: medium. Source dates: 2019-10-26 / 2023-11-11.

{
  "product": "windows",
  "service": "security",
  "definition": "Requirements: Audit Policy : Security Settings/Local Policies/Audit Policy, Registry System Access Control (SACL): Auditing/User"
}

Pinned original Sigma rule · Detection Rule License 1.1

Source SHA-256: 3394f6d4f07eed4dfb1263ddab520164a9f3e1a883be8c7d620042e38a0ec703

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 Defender Exclusion Registry Key - Write Access Requested
id: e9c8808f-4cfb-4ba9-97d4-e5f3beaa244d
related:
    - id: 46a68649-f218-4f86-aea1-16a759d81820
      type: derived
    - id: a33f8808-2812-4373-ae95-8cfb82134978
      type: derived
status: test
description: |
    Detects write access requests to the Windows Defender exclusions registry keys. This could be an indication of an attacker trying to request a handle or access the object to write new exclusions in order to bypass security.
references:
    - https://www.bleepingcomputer.com/news/security/gootkit-malware-bypasses-windows-defender-by-setting-path-exclusions/
author: '@BarryShooshooga, Nasreddine Bencherchali (Nextron Systems)'
date: 2019-10-26
modified: 2023-11-11
tags:
    - attack.defense-impairment
    - attack.t1685
logsource:
    product: windows
    service: security
    definition: 'Requirements: Audit Policy : Security Settings/Local Policies/Audit Policy, Registry System Access Control (SACL): Auditing/User'
detection:
    selection:
        AccessList|contains:
            - '%%4417' # WriteData
            - '%%4418' # AppendData
        EventID:
            - 4656 # A handle to an object was requested.
            - 4663 # An attempt was made to access an object.
        ObjectName|contains: '\Microsoft\Windows Defender\Exclusions\'
    condition: selection
falsepositives:
    - Unknown
level: medium

Original YAML and metadata in JSON

False positives

• Unknown

Source references

• https://www.bleepingcomputer.com/news/security/gootkit-malware-bypasses-windows-defender-by-setting-path-exclusions/