detection.wiki

Detection rules › Sigma

UAC Bypass Using Disk Cleanup

Status
test
Severity
high
Log source
product windows, category process_creation
Author
Christian Burkard (Nextron Systems)
Source
github.com/SigmaHQ/sigma

Detects the pattern of UAC Bypass using scheduled tasks and variable expansion of cleanmgr.exe (UACMe 34)

MITRE ATT&CK coverage

TacticTechniques
Privilege EscalationT1548.002 Abuse Elevation Control Mechanism: Bypass User Account Control

Event coverage

ProviderEventTitle
SysmonEvent ID 1Process creation

Rule body yaml

title: UAC Bypass Using Disk Cleanup
id: b697e69c-746f-4a86-9f59-7bfff8eab881
status: test
description: Detects the pattern of UAC Bypass using scheduled tasks and variable expansion of cleanmgr.exe (UACMe 34)
references:
    - https://github.com/hfiref0x/UACME
author: Christian Burkard (Nextron Systems)
date: 2021-08-30
modified: 2024-12-01
tags:
    - attack.privilege-escalation
    - attack.t1548.002
logsource:
    category: process_creation
    product: windows
detection:
    selection:
        CommandLine|endswith: '"\system32\cleanmgr.exe /autoclean /d C:'
        ParentCommandLine: 'C:\Windows\system32\svchost.exe -k netsvcs -p -s Schedule'
        IntegrityLevel:
            - 'High'
            - 'System'
            - 'S-1-16-16384' # System
            - 'S-1-16-12288' # High
    condition: selection
falsepositives:
    - Unknown
level: high

Stages and Predicates

Stage 0: condition

selection

Stage 1: selection

selection:
    CommandLine|endswith: '"\system32\cleanmgr.exe /autoclean /d C:'
    ParentCommandLine: 'C:\Windows\system32\svchost.exe -k netsvcs -p -s Schedule'
    IntegrityLevel:
        - 'High'
        - 'System'
        - 'S-1-16-16384'
        - 'S-1-16-12288'

Indicators

Each row is a field, operator, and value that the rule matches. The corpus column counts how many other rules in the catalog look for the same combination: high numbers point to widely-used, community-vetted indicators. Blank or 1 shows that the indicator is specific to this rule.

FieldKindValues
CommandLineends_with
  • "\system32\cleanmgr.exe /autoclean /d C:
IntegrityLeveleq
  • High corpus 21 (sigma 17, kusto 3, splunk 1)
  • S-1-16-12288 corpus 21 (sigma 17, kusto 3, splunk 1)
  • S-1-16-16384 corpus 29 (sigma 22, splunk 4, elastic 3)
  • System corpus 29 (sigma 22, splunk 4, elastic 3)
ParentCommandLineeq
  • C:\Windows\system32\svchost.exe -k netsvcs -p -s Schedule