Detectionhightest
Explorer NOUACCHECK Flag
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
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Launch
Florian Roth (Nextron Systems)Created Wed Feb 23Updated Thu Apr 21534f2ef7-e8a2-4433-816d-c91bccde289bwindows
Log Source
WindowsProcess Creation
ProductWindows← raw: windows
CategoryProcess Creation← raw: process_creation
Events generated when a new process is spawned on the system. Covers command-line arguments, parent/child relationships, and process metadata.
Detection Logic
Detection Logic2 selectors
detection:
selection:
Image|endswith: '\explorer.exe'
CommandLine|contains: '/NOUACCHECK'
filter_dc_logon:
- ParentCommandLine: 'C:\Windows\system32\svchost.exe -k netsvcs -p -s Schedule'
- ParentImage: 'C:\Windows\System32\svchost.exe' # coarse filter needed for ID 4688 Events
condition: selection and not 1 of filter_*False Positives
Domain Controller User Logon
Unknown how many legitimate software products use that method
References
MITRE ATT&CK
Rule Metadata
Rule ID
534f2ef7-e8a2-4433-816d-c91bccde289b
Status
test
Level
high
Type
Detection
Created
Wed Feb 23
Modified
Thu Apr 21
Path
rules/windows/process_creation/proc_creation_win_explorer_nouaccheck.yml
Raw Tags
attack.privilege-escalationattack.defense-evasionattack.t1548.002