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

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

FreeUnreviewedSigmahighv1

windows-registry-change-disabling-windefend-service-windefend-start-4-e1aa95de

title: Windows Registry Change Disabling WinDefend Service (WinDefend Start=4)
id: 46b57e68-a76a-4f99-a8c6-fbb02106bb0f
status: test
description: 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.
references:
  - https://thedfirreport.com/2021/10/18/icedid-to-xinglocker-ransomware-in-24-hours/
  - https://gist.github.com/anadr/7465a9fde63d41341136949f14c21105
  - https://github.com/SigmaHQ/sigma/blob/master/rules/windows/registry/registry_set/registry_set_disable_windows_defender_service.yml
author: Ján Trenčanský, frack113, AlertIQ, Nasreddine Bencherchali, Huntrule Team
date: 2022-08-01
modified: 2024-03-25
tags:
  - attack.defense-impairment
  - attack.t1685
logsource:
  product: windows
  category: registry_set
detection:
  selection:
    TargetObject|endswith: \Services\WinDefend\Start
    Details: DWORD (0x00000004)
  condition: selection
falsepositives:
  - Administrator actions
level: high
license: DRL-1.1
related:
  - id: e1aa95de-610a-427d-b9e7-9b46cfafbe6a
    type: derived

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.

Known false positives

Administrator actions

Detection content is published as a reviewed draft. Tune thresholds and exclusions against your own telemetry before enabling this rule for alerting.