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Windows AMSI Provider Registry Key Deletion (HKLM\Software\Microsoft\AMSI)

Alerts on deletion of AMSI provider registry key entries under HKLM\Software\Microsoft\AMSI, potentially indicating AMSI inspection impairment.

FreeReviewedSigma · High · v1
Product
windows
Category
registry_delete
Author
frack113 (SigmaHQ), DRL 1.1
Published
2021-06-07
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 deletion of specific AMSI provider registry key entries under HKLM\Software\Microsoft\AMSI. Removing these entries can be used by an attacker to impair or disable AMSI-based inspection. The detection relies on Windows registry delete telemetry for the matching TargetObject identifiers, with exclusions for common Windows Defender platform activity associated with MsMpEng.exe.

Reporting behind it

Related detections9 linkedT1685 — drag to rearrange
Malicious Microsoft Defender Tampering via PowerShell Preference Cmdlets
Suspicious Windows Defender Exclusion via Add-MpPreference (via process_creation)
Malicious Windows Defender Service Tampering via PowerShell (via process_creation)
Windows Defender Disabled via DisableAntiSpyware Registry Key
Suspicious Vulnerable Intel Ethernet Driver Load for BYOVD via SCATTERED SPIDER (via driver_load)
Malicious Defender Disable And Executable Exclusion Via Registry
Malicious UAC Disable via EnableLUA Registry Modification (via registry_set)
Malicious AMSI and ETW Patching via PowerShell Script
Malicious PowMix AMSI Bypass via amsiInitFailed
Windows AMSI Provider Registry Key Deletion (HKLM\Software\Microsoft\AMSI)
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.