Malicious Security Product Bypass via defendnot Loader

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 execution of the defendnot loader, a tool analyzed by Huntress that registers a fake antivirus through the Windows Security Center API to silently disable Microsoft Defender. The loader drops a ctx.bin configuration and injects defendnot.dll into taskmgr.exe to persist the fake AV registration. Because defendnot exists solely to neutralize Defender, its execution is a high-confidence defense-evasion indicator.

Reporting behind it

Related detections9 linkedT1685 — drag to rearrange

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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 Security Product Bypass via defendnot Loader

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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