Malicious Whole-Drive Defender Exclusion via Add-MpPreference (via ps_script)

PremiumReviewedSigma · High · v1
Product
windows
Category
ps_script
Author
HuntRule
Published
2026-09-22
Updated
2026-09-22

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 detects a PowerShell command adding the entire C drive as a Microsoft Defender exclusion path via Add-MpPreference, the defense-evasion step used by the D3F@ck MaaS loader before dropping payloads. Excluding the whole system drive from scanning is never a legitimate administrative action and effectively blinds Defender. This precedes RegAsm.exe injection of Raccoon Stealer.

Related detections9 linkedT1685 — drag to rearrange
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Suspicious Service binPath Hijack Followed by System Reboot
Malicious Windows Defender Root Exclusion via Add-MpPreference (via process_creation)
Suspicious Modification of Windows Hosts File
Malicious AMSI and ETW Bypass via In-Memory Patching (via ps_script)
Suspicious PowerShell AMSI or ETW Tampering
Malicious ABYSSWORKER EDR-Killer Driver Load via smuol.sys
Suspicious WMI Query Against Windows Defender Namespace via wmic (via process_creation)
Malicious Microsoft Defender Tampering via PowerShell Preference Cmdlets
Malicious Whole-Drive Defender Exclusion via Add-MpPreference (via ps_script)
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.