Detectionhightest

Potential PowerShell Execution Via DLL

Detects potential PowerShell execution from a DLL instead of the usual PowerShell process as seen used in PowerShdll. This detection assumes that PowerShell commands are passed via the CommandLine.

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Markus Neis, Nasreddine Bencherchali (Nextron Systems)Created Sat Aug 25Updated Thu Mar 076812a10b-60ea-420c-832f-dfcc33b646bawindows

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:
        - Image|endswith:
              - '\InstallUtil.exe'
              - '\RegAsm.exe'
              - '\RegSvcs.exe'
              - '\regsvr32.exe'
              - '\rundll32.exe'
        - OriginalFileName:
              - 'InstallUtil.exe'
              - 'RegAsm.exe'
              - 'RegSvcs.exe'
              - 'REGSVR32.EXE'
              - 'RUNDLL32.EXE'
    selection_cli:
        CommandLine|contains:
            - 'Default.GetString'
            - 'DownloadString'
            - 'FromBase64String'
            - 'ICM '
            - 'IEX '
            - 'Invoke-Command'
            - 'Invoke-Expression'
    condition: all of selection_*