Suspicious Windows Defender Registry Key Tampering Via Reg.EXE — Sigma Rule

Rule metadata and linked tags

Author: Florian Roth (Nextron Systems), Swachchhanda Shrawan Poudel, Nasreddine Bencherchali (Nextron Systems). Source status: test; severity: high. Source dates: 2022-03-22 / 2025-06-04.

{
  "category": "process_creation",
  "product": "windows"
}

Pinned original Sigma rule · Detection Rule License 1.1

Source SHA-256: 83118f134300400efd8948c383554bc89f99bd1719e0ac65d695808cd807e665

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: Suspicious Windows Defender Registry Key Tampering Via Reg.EXE
id: 452bce90-6fb0-43cc-97a5-affc283139b3
status: test
description: |
    Detects the usage of "reg.exe" to tamper with different Windows Defender registry keys in order to disable some important features related to protection and detection
references:
    - https://thedfirreport.com/2022/03/21/apt35-automates-initial-access-using-proxyshell/
    - https://github.com/swagkarna/Defeat-Defender-V1.2.0/tree/ae4059c4276da6f6303b8f53cdff085ecae88a91
    - https://www.elevenforum.com/t/video-guide-how-to-completely-disable-microsoft-defender-antivirus.14608/page-2
    - https://tria.ge/241231-j9yatstqbm/behavioral1
author: Florian Roth (Nextron Systems), Swachchhanda Shrawan Poudel, Nasreddine Bencherchali (Nextron Systems)
date: 2022-03-22
modified: 2025-06-04
tags:
    - attack.defense-impairment
    - attack.t1685
logsource:
    category: process_creation
    product: windows
detection:
    selection_root_img:
        - Image|endswith: '\reg.exe'
        - OriginalFileName: 'reg.exe'
    selection_root_path:
        CommandLine|contains:
            - 'SOFTWARE\Microsoft\Windows Defender\'
            - 'SOFTWARE\Policies\Microsoft\Windows Defender Security Center'
            - 'SOFTWARE\Policies\Microsoft\Windows Defender\'
    selection_dword_0:
        CommandLine|contains|all:
            - ' add '
            - 'd 0'
        CommandLine|contains:
            - 'DisallowExploitProtectionOverride'
            - 'EnableControlledFolderAccess'
            - 'MpEnablePus'
            - 'PUAProtection'
            - 'SpynetReporting'
            - 'SubmitSamplesConsent'
            - 'TamperProtection'
    selection_dword_1:
        CommandLine|contains|all:
            - ' add '
            - 'd 1'
        CommandLine|contains:
            - 'DisableAccess'
            - 'DisableAntiSpyware'
            - 'DisableAntiSpywareRealtimeProtection'
            - 'DisableAntiVirus'
            - 'DisableAntiVirusSignatures'
            - 'DisableArchiveScanning'
            - 'DisableBehaviorMonitoring'
            - 'DisableBlockAtFirstSeen'
            - 'DisableCloudProtection'
            - 'DisableConfig'
            - 'DisableEnhancedNotifications'
            - 'DisableIntrusionPreventionSystem'
            - 'DisableIOAVProtection'
            - 'DisableNetworkProtection'
            - 'DisableOnAccessProtection'
            - 'DisablePrivacyMode'
            - 'DisableRealtimeMonitoring'
            - 'DisableRoutinelyTakingAction'
            - 'DisableScanOnRealtimeEnable'
            - 'DisableScriptScanning'
            - 'DisableSecurityCenter'
            - 'Notification_Suppress'
            - 'SignatureDisableUpdateOnStartupWithoutEngine'
    condition: all of selection_root_* and 1 of selection_dword_*
falsepositives:
    - Rare legitimate use by administrators to test software (should always be investigated)
level: high

Original YAML and metadata in JSON

False positives

• Rare legitimate use by administrators to test software (should always be investigated)

Source references

• https://thedfirreport.com/2022/03/21/apt35-automates-initial-access-using-proxyshell/
• https://github.com/swagkarna/Defeat-Defender-V1.2.0/tree/ae4059c4276da6f6303b8f53cdff085ecae88a91
• https://www.elevenforum.com/t/video-guide-how-to-completely-disable-microsoft-defender-antivirus.14608/page-2
• https://tria.ge/241231-j9yatstqbm/behavioral1