UAC Bypass Tools Using ComputerDefaults

Hunt Hypothesis

Detects tools such as UACMe used to bypass UAC with computerdefaults.exe (UACMe 59)

Detection Rule

Sigma (Original)

title: UAC Bypass Tools Using ComputerDefaults
id: 3c05e90d-7eba-4324-9972-5d7f711a60a8
status: test
description: Detects tools such as UACMe used to bypass UAC with computerdefaults.exe (UACMe 59)
references:
    - https://github.com/hfiref0x/UACME
author: Christian Burkard (Nextron Systems)
date: 2021-08-31
modified: 2024-12-01
tags:
    - attack.privilege-escalation
    - attack.t1548.002
logsource:
    category: process_creation
    product: windows
detection:
    selection:
        IntegrityLevel:
            - 'High'
            - 'System'
            - 'S-1-16-16384' # System
            - 'S-1-16-12288' # High
        Image: 'C:\Windows\System32\ComputerDefaults.exe'
    filter:
        ParentImage|contains:
            - ':\Windows\System32'
            - ':\Program Files'
    condition: selection and not filter
falsepositives:
    - Unknown
level: high

KQL (Azure Sentinel)

imProcessCreate
| where ((TargetProcessIntegrityLevel in~ ("High", "System", "S-1-16-16384", "S-1-16-12288")) and TargetProcessName =~ "C:\\Windows\\System32\\ComputerDefaults.exe") and (not(((ParentProcessName contains ":\\Windows\\System32" or ParentProcessName contains ":\\Program Files") or (ActingProcessName contains ":\\Windows\\System32" or ActingProcessName contains ":\\Program Files"))))

Required Data Sources

False Positive Guidance

• Unknown

MITRE ATT&CK Context

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

References

• https://github.com/hfiref0x/UACME
• SigmaHQ Rule