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Windows: reg.exe Registry Tampering of Windows Defender Policy Keys

Detects reg.exe adding Defender DWORD policy values to disable or suppress multiple protection features via Windows registry.

FreeReviewedSigma · High · v1
Product
windows
Category
process_creation
Author
Florian Roth (Nextron Systems), Swachchhanda Shrawan Poudel, Nasreddine Bencherchali (Nextron Systems) (SigmaHQ), DRL 1.1
Published
2022-03-22
Updated
2026-07-30
AnalysisDetection

ATT&CK techniques

  1. Recon

  2. Resource Dev

  3. Initial Access

  4. Execution

  5. Persistence

  6. Priv Esc

  7. Defense Evasion

  8. Cred Access

  9. Discovery

  10. Lateral Movement

  11. Collection

  12. C2

  13. Exfiltration

  14. Impact

What it detects

This rule flags process creation where reg.exe is used to modify Windows Defender-related registry paths under both default and policy locations. The matched command lines add DWORD values associated with multiple Defender protection, reporting, and tamper protection settings, which is consistent with attempts to weaken endpoint defenses. It relies on telemetry from Windows process creation, including the process image and full command line content, to identify the specific registry targets and the presence of disabling-related DWORD operations.

Reporting behind it

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Malicious AMSI and ETW Patching via PowerShell Script
Malicious PowMix AMSI Bypass via amsiInitFailed
Suspicious ThrottleStop Driver Abuse for Defense Evasion in Ransomware Attacks
Malicious Disabling of Microsoft Defender Real-Time Protection via SystemSettingsAdminFlows by DeadLock Ransomware
Suspicious Security Software Uninstallation via WMIC Product Call Uninstall (Chaos Ransomware)
Suspicious Security Product Uninstall via wmic product call uninstall
Windows: reg.exe Registry Tampering of Windows Defender Policy Keys
Pivot detection · T1685 · 9 related

Detection content is published as a reviewed draft. Tune thresholds and exclusions against your own telemetry before enabling this rule for alerting.