Windows Defender Configuration Changes — Sigma Rule

Rule metadata and linked tags

Author: Nasreddine Bencherchali (Nextron Systems). Source status: stable; severity: high. Source dates: 2022-12-06 / 2023-11-24.

{
  "product": "windows",
  "service": "windefend"
}

Pinned original Sigma rule · Detection Rule License 1.1

Source SHA-256: fffa0b02005cee99d6ddbe9367a5428aecbce2133b65524e9aae70e30b004b83

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 Configuration Changes
id: 801bd44f-ceed-4eb6-887c-11544633c0aa
related:
    - id: 1321dc4e-a1fe-481d-a016-52c45f0c8b4f
      type: similar
    - id: a3ab73f1-bd46-4319-8f06-4b20d0617886
      type: similar
    - id: 91903aba-1088-42ee-b680-d6d94fe002b0
      type: similar
status: stable
description: Detects suspicious changes to the Windows Defender configuration
references:
    - https://learn.microsoft.com/en-us/defender-endpoint/troubleshoot-microsoft-defender-antivirus?view=o365-worldwide
    - https://bidouillesecurity.com/disable-windows-defender-in-powershell/#DisableAntiSpyware
author: Nasreddine Bencherchali (Nextron Systems)
date: 2022-12-06
modified: 2023-11-24
tags:
    - attack.defense-impairment
    - attack.t1685
logsource:
    product: windows
    service: windefend
detection:
    selection:
        EventID: 5007 # The antimalware platform configuration changed.
        NewValue|contains:
            # TODO: Add more suspicious values
            - '\Windows Defender\DisableAntiSpyware '
            # - '\Windows Defender\Features\TamperProtection ' # Might produce FP
            - '\Windows Defender\Scan\DisableRemovableDriveScanning '
            - '\Windows Defender\Scan\DisableScanningMappedNetworkDrivesForFullScan '
            - '\Windows Defender\SpyNet\DisableBlockAtFirstSeen '
            - '\Real-Time Protection\SpyNetReporting '
            # Exclusions changes are covered in 1321dc4e-a1fe-481d-a016-52c45f0c8b4f
            # Exploit guard changes are covered in a3ab73f1-bd46-4319-8f06-4b20d0617886
    condition: selection
falsepositives:
    - Administrator activity (must be investigated)
level: high

Original YAML and metadata in JSON

False positives

• Administrator activity (must be investigated)

Source references

• https://learn.microsoft.com/en-us/defender-endpoint/troubleshoot-microsoft-defender-antivirus?view=o365-worldwide
• https://bidouillesecurity.com/disable-windows-defender-in-powershell/#DisableAntiSpyware