Windows Registry: Enable RDP Remote Assistance via fAllowToGetHelp

Alerts when Windows enables remote assistance via Terminal Server fAllowToGetHelp (0x1) registry change.

FreeUnreviewedSigmamediumv1
title: "Windows Registry: Enable RDP Remote Assistance via fAllowToGetHelp"
id: 1b0dc84a-d1eb-42c7-80d7-0b8217d64981
status: test
description: This rule flags changes to the Windows Terminal Server setting fAllowToGetHelp being set to DWORD 0x00000001. Enabling this feature can allow remote help/assistance connections, which may be abused to gain interactive access. The detection relies on registry set telemetry for the specific value under System\CurrentControlSet\Control\Terminal Server\fAllowToGetHelp. Investigate to confirm the change was authorized and expected for the affected system.
references:
  - https://github.com/redcanaryco/atomic-red-team/blob/40b77d63808dd4f4eafb83949805636735a1fd15/atomics/T1112/T1112.md
  - https://github.com/SigmaHQ/sigma/blob/master/rules/windows/registry/registry_set/registry_set_allow_rdp_remote_assistance_feature.yml
author: frack113, Huntrule Team
date: 2022-08-19
modified: 2023-08-17
tags:
  - attack.persistence
  - attack.defense-impairment
  - attack.t1112
logsource:
  category: registry_set
  product: windows
detection:
  selection:
    TargetObject|endswith: System\CurrentControlSet\Control\Terminal Server\fAllowToGetHelp
    Details: DWORD (0x00000001)
  condition: selection
falsepositives:
  - Legitimate use of the feature (alerts should be investigated either way)
level: medium
regression_tests_path: regression_data/rules/windows/registry/registry_set/registry_set_allow_rdp_remote_assistance_feature/info.yml
simulation:
  - type: atomic-red-team
    name: Allow RDP Remote Assistance Feature
    technique: T1112
    atomic_guid: 86677d0e-0b5e-4a2b-b302-454175f9aa9e
license: DRL-1.1
related:
  - id: 37b437cf-3fc5-4c8e-9c94-1d7c9aff842b
    type: derived

What it detects

This rule flags changes to the Windows Terminal Server setting fAllowToGetHelp being set to DWORD 0x00000001. Enabling this feature can allow remote help/assistance connections, which may be abused to gain interactive access. The detection relies on registry set telemetry for the specific value under System\CurrentControlSet\Control\Terminal Server\fAllowToGetHelp. Investigate to confirm the change was authorized and expected for the affected system.

Known false positives

  • Legitimate use of the feature (alerts should be investigated either way)

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