Windows Registry: UAC PromptOnSecureDesktop Disabled

Detects setting UAC PromptOnSecureDesktop to 0 via Windows registry policy, disabling secure desktop for UAC prompts.

FreeUnreviewedSigmamediumv1

windows-registry-uac-promptonsecuredesktop-disabled-0d7ceeef

title: "Windows Registry: UAC PromptOnSecureDesktop Disabled"
id: 75676bf4-3ec4-4d67-8af5-56baa5a307c9
related:
  - id: c5f6a85d-b647-40f7-bbad-c10b66bab038
    type: similar
  - id: 48437c39-9e5f-47fb-af95-3d663c3f2919
    type: similar
  - id: 0d7ceeef-3539-4392-8953-3dc664912714
    type: derived
status: test
description: This rule flags registry changes that set the UAC "PromptOnSecureDesktop" policy value to 0 under the System Policies path. Disabling secure desktop display can expose UAC prompts to the user’s normal desktop, reducing protection against prompt spoofing or tampering. It relies on registry set telemetry that records the TargetObject path and the associated DWORD setting value.
references:
  - https://github.com/redcanaryco/atomic-red-team/blob/7e11e9b79583545f208a6dc3fa062f2ed443d999/atomics/T1548.002/T1548.002.md
  - https://github.com/SigmaHQ/sigma/blob/master/rules/windows/registry/registry_set/registry_set_uac_disable_secure_desktop_prompt.yml
author: frack113, Huntrule Team
date: 2024-05-10
tags:
  - attack.privilege-escalation
  - attack.t1548.002
logsource:
  category: registry_set
  product: windows
detection:
  selection:
    TargetObject|contains: \Microsoft\Windows\CurrentVersion\Policies\System\PromptOnSecureDesktop
    Details: DWORD (0x00000000)
  condition: selection
falsepositives:
  - Unknown
level: medium
license: DRL-1.1

What it detects

This rule flags registry changes that set the UAC "PromptOnSecureDesktop" policy value to 0 under the System Policies path. Disabling secure desktop display can expose UAC prompts to the user’s normal desktop, reducing protection against prompt spoofing or tampering. It relies on registry set telemetry that records the TargetObject path and the associated DWORD setting value.

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.