UAC Secure Desktop Prompt Disabled

Hunt Hypothesis

Detects when an attacker tries to change User Account Control (UAC) elevation request destination via the “PromptOnSecureDesktop” value. The “PromptOnSecureDesktop” setting specifically determines whe

Detection Rule

Sigma (Original)

title: UAC Secure Desktop Prompt Disabled
id: 0d7ceeef-3539-4392-8953-3dc664912714
related:
    - id: c5f6a85d-b647-40f7-bbad-c10b66bab038
      type: similar
    - id: 48437c39-9e5f-47fb-af95-3d663c3f2919
      type: similar
status: test
description: |
    Detects when an attacker tries to change User Account Control (UAC) elevation request destination via the "PromptOnSecureDesktop" value.
    The "PromptOnSecureDesktop" setting specifically determines whether UAC prompts are displayed on the secure desktop. The secure desktop is a separate desktop environment that's isolated from other processes running on the system. It's designed to prevent malicious software from intercepting or tampering with UAC prompts.
    When "PromptOnSecureDesktop" is set to 0, UAC prompts are displayed on the user's current desktop instead of the secure desktop. This reduces the level of security because it potentially exposes the prompts to manipulation by malicious software.
references:
    - https://github.com/redcanaryco/atomic-red-team/blob/7e11e9b79583545f208a6dc3fa062f2ed443d999/atomics/T1548.002/T1548.002.md
author: frack113
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

KQL (Azure Sentinel)

imRegistry
| where RegistryKey contains "\\Microsoft\\Windows\\CurrentVersion\\Policies\\System\\PromptOnSecureDesktop" and RegistryValueData =~ "DWORD (0x00000000)"

KQL (Microsoft 365 Defender)

DeviceRegistryEvents
| where RegistryKey contains "\\Microsoft\\Windows\\CurrentVersion\\Policies\\System\\PromptOnSecureDesktop" and RegistryValueData =~ "DWORD (0x00000000)"

Required Data Sources

False Positive Guidance

• Unknown

MITRE ATT&CK Context

• Tactic: Privilege Escalation
• Technique: T1548.002 — T1548.002

References

• https://github.com/redcanaryco/atomic-red-team/blob/7e11e9b79583545f208a6dc3fa062f2ed443d999/atomics/T1548.002/T1548.002.md
• SigmaHQ Rule