Explorer NOUACCHECK Flag

 1title: Explorer NOUACCHECK Flag
 2id: 534f2ef7-e8a2-4433-816d-c91bccde289b
 3status: test
 4description: Detects suspicious starts of explorer.exe that use the /NOUACCHECK flag that allows to run all sub processes of that newly started explorer.exe without any UAC checks
 5references:
 6    - https://twitter.com/ORCA6665/status/1496478087244095491
 7author: Florian Roth (Nextron Systems)
 8date: 2022-02-23
 9modified: 2022-04-21
10tags:
11    - attack.defense-evasion
12    - attack.t1548.002
13logsource:
14    category: process_creation
15    product: windows
16detection:
17    selection:
18        Image|endswith: '\explorer.exe'
19        CommandLine|contains: '/NOUACCHECK'
20    filter_dc_logon:
21        - ParentCommandLine: 'C:\Windows\system32\svchost.exe -k netsvcs -p -s Schedule'
22        - ParentImage: 'C:\Windows\System32\svchost.exe' # coarse filter needed for ID 4688 Events
23    condition: selection and not 1 of filter_*
24falsepositives:
25    - Domain Controller User Logon
26    - Unknown how many legitimate software products use that method
27level: high