Suspicious Windows Defender Real-Time Protection Disabled via Policy Registry by Cephalus Ransomware

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 registry changes under the Windows Defender Real-Time Protection policy key that disable on-access and real-time scanning, a defense evasion step used by Cephalus ransomware. Turning off these protections lets the encryptor run without interference.

Reporting behind it

Related detections9 linkedT1685 — drag to rearrange

Windows Defender Tampering via Set-MpPreference and Exclusions

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Malicious Windows Defender Tampering via Set-MpPreference (via process_creation)

Malicious Container Runtime Tampering via chmod on runc (via process_creation)

In-Memory AMSI or ETW Bypass in PowerShell (via process_creation)

Malicious Microsoft Defender Critical Security Components Disabled - Command (via process_creation)

Malicious Microsoft Defender Service Deactivation Attempt - Command (via process_creation)

Malicious Wdigest Authentication Enabled - Reg via Command (via process_creation)

Malicious Tampering With Windows Defender Protection (via process_creation)

Suspicious Windows Defender Real-Time Protection Disabled via Policy Registry by Cephalus Ransomware

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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