Malicious Defender Threat Action Override via Set-MpPreference

ATT&CK techniques

Recon
Resource Dev
Initial Access
Execution
Persistence
Priv Esc
Defense Evasion
Cred Access
Discovery
Lateral Movement
Collection
C2
Exfiltration
Impact

What it detects

This rule detects Set-MpPreference configuring SevereThreatDefaultAction to Allow (6) so Microsoft Defender takes no action on severe detections. This weakens protection while leaving the AV appearing enabled, a subtle evasion used in enduring ransomware playbooks. Setting default threat actions to allow lets malware execute despite detection.

Reporting behind it

Related detections9 linkedT1685 — drag to rearrange

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Suspicious Windows Defender Exclusion Added for Entire Windows Directory

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Malicious Defender Threat Action Override via Set-MpPreference

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.

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