Detectionmediumtest

Permission Check Via Accesschk.EXE

Detects the usage of the "Accesschk" utility, an access and privilege audit tool developed by SysInternal and often being abused by attacker to verify process privileges

Convert In Phoenix Studio

Open this Sigma rule in the converter with the YAML preloaded and ready for backend selection.

Launch

Teymur Kheirkhabarov, Mangatas Tondang, oscd.community, Nasreddine Bencherchali (Nextron Systems)Created Tue Oct 13Updated Mon Feb 20c625d754-6a3d-4f65-9c9a-536aea960d37windows

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:
    selection_img:
        - Product|endswith: 'AccessChk'
        - Description|contains: 'Reports effective permissions'
        - Image|endswith:
              - '\accesschk.exe'
              - '\accesschk64.exe'
        - OriginalFileName: 'accesschk.exe'
    selection_cli:
        CommandLine|contains: # These are the most common flags used with this tool. You could add other combinations if needed
            - 'uwcqv '
            - 'kwsu '
            - 'qwsu '
            - 'uwdqs '
    condition: all of selection*