Windows WerFault ReflectDebugger Registry Key Value Targeting

Flags registry set events targeting WerFault ReflectDebugger under Windows Error Reporting Hangs for potential persistence abuse.

FreeUnreviewedSigmahighv1

windows-werfault-reflectdebugger-registry-key-value-targeting-0cf2e1c6

title: Windows WerFault ReflectDebugger Registry Key Value Targeting
id: 44808c5f-1694-4003-bde0-251c8983aac0
related:
  - id: fabfb3a7-3ce1-4445-9c7c-3c27f1051cdd
    type: derived
  - id: 0cf2e1c6-8d10-4273-8059-738778f981ad
    type: derived
status: test
description: This rule matches registry set activity targeting the ReflectDebugger value path under the Windows Error Reporting Hangs key associated with WerFault. Attackers can abuse this location to establish persistence or influence debugging/behavior of error handling components. The detection relies on Windows registry set telemetry that includes the TargetObject path ending with the specified ReflectDebugger location.
references:
  - https://cocomelonc.github.io/malware/2022/11/02/malware-pers-18.html
  - https://www.hexacorn.com/blog/2018/08/31/beyond-good-ol-run-key-part-85/
  - https://github.com/SigmaHQ/sigma/blob/master/rules/windows/registry/registry_set/registry_set_persistence_reflectdebugger.yml
author: X__Junior, Huntrule Team
date: 2023-05-18
tags:
  - attack.stealth
  - attack.t1036.003
logsource:
  category: registry_set
  product: windows
detection:
  selection:
    TargetObject|endswith: \Microsoft\Windows\Windows Error Reporting\Hangs\ReflectDebugger
  condition: selection
falsepositives:
  - Unknown
level: high
license: DRL-1.1

What it detects

This rule matches registry set activity targeting the ReflectDebugger value path under the Windows Error Reporting Hangs key associated with WerFault. Attackers can abuse this location to establish persistence or influence debugging/behavior of error handling components. The detection relies on Windows registry set telemetry that includes the TargetObject path ending with the specified ReflectDebugger location.

Known false positives

Unknown

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