Disable Tamper Protection on Windows Defender

Hunt Hypothesis

Detects disabling Windows Defender Tamper Protection

Detection Rule

Sigma (Original)

title: Disable Tamper Protection on Windows Defender
id: 93d298a1-d28f-47f1-a468-d971e7796679
status: test
description: Detects disabling Windows Defender Tamper Protection
references:
    - https://www.tenforums.com/tutorials/123792-turn-off-tamper-protection-microsoft-defender-antivirus.html
author: Austin Songer @austinsonger
date: 2021-08-04
modified: 2023-08-17
tags:
    - attack.defense-impairment
    - attack.t1685
logsource:
    category: registry_set
    product: windows
detection:
    selection:
        TargetObject|contains: '\Microsoft\Windows Defender\Features\TamperProtection'
        Details: DWORD (0x00000000)
    filter_msmpeng_client: # only disabled temporarily during updates
        Image|startswith: 'C:\ProgramData\Microsoft\Windows Defender\Platform\'
        Image|endswith: '\MsMpEng.exe'
    filter_msmpeng_domain_controller: # only disabled temporarily during updates
        Image: 'C:\Program Files\Windows Defender\MsMpEng.exe'
    condition: selection and not 1 of filter_*
falsepositives:
    - Unknown
level: medium

KQL (Azure Sentinel)

imRegistry
| where (RegistryKey contains "\\Microsoft\\Windows Defender\\Features\\TamperProtection" and RegistryValueData =~ "DWORD (0x00000000)") and (not(((ActingProcessName startswith "C:\\ProgramData\\Microsoft\\Windows Defender\\Platform\\" and ActingProcessName endswith "\\MsMpEng.exe") or ActingProcessName =~ "C:\\Program Files\\Windows Defender\\MsMpEng.exe")))

Required Data Sources

False Positive Guidance

• Unknown

MITRE ATT&CK Context

• Technique: T1685 — T1685

References

• https://www.tenforums.com/tutorials/123792-turn-off-tamper-protection-microsoft-defender-antivirus.html
• SigmaHQ Rule