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 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
Suspicious ThrottleStop Driver Abuse for Defense Evasion in Ransomware Attacks
Malicious Disabling of Microsoft Defender Real-Time Protection via SystemSettingsAdminFlows by DeadLock Ransomware
Suspicious Security Software Uninstallation via WMIC Product Call Uninstall (Chaos Ransomware)
Suspicious Security Product Uninstall via wmic product call uninstall
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.