huntrule

Windows Registry Change Disabling WinDefend Service (WinDefend Start=4)

Flags registry changes that set WinDefend service Start to 0x4, indicating potential defensive impairment.

FreeReviewedSigma · High · v1
Product
windows
Category
registry_set
Author
Ján Trenčanský, frack113, AlertIQ, Nasreddine Bencherchali (SigmaHQ), DRL 1.1
Published
2022-08-01
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 identifies registry writes that set the Windows Defender service start value for WinDefend by targeting the Services\WinDefend\Start registry path and matching a DWORD value of 0x00000004. Disabling or altering security service behavior can reduce endpoint defenses and enable subsequent malicious activity. Detection relies on Windows registry set telemetry capturing the TargetObject and Details fields for the modified Start value.

Reporting behind it

Related detections9 linkedT1685 — drag to rearrange
Suspicious Windows Defender Exclusion of User Profile via PowerShell (via process_creation)
Malicious Vulnerable Driver Service Creation for BYOVD (via process_creation)
Malicious Microsoft Defender Disabled via Registry DisableAntiSpyware (via process_creation)
Suspicious Termination of Defender Tray Process via Taskkill
Malicious Windows Defender Disablement via MpCmdRun RemoveDefinitions
Malicious Unsigned VIB Installation on ESXi Host via esxcli (via process_creation)
Suspicious In-Memory PowerShell Execution from Web Server via Automation Assembly (via image_load)
Malicious EDR Evasion Driver Load from AnyDesk Directory via k.sys (via image_load)
Malicious Zemana Vulnerable Driver Load for EDR Termination (via image_load)
Windows Registry Change Disabling WinDefend Service (WinDefend Start=4)
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.