Detectionhightest

Suspicious PowerShell Parameter Substring

Detects suspicious PowerShell invocation with a parameter substring

Convert In Phoenix Studio

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

Florian Roth (Nextron Systems), Daniel Bohannon, Roberto Rodriguez (Cyb3rWard0g)Created Wed Jan 16Updated Thu Jul 1436210e0d-5b19-485d-a087-c096088885f0windows

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:
        Image|endswith:
            - '\powershell.exe'
            - '\pwsh.exe'
        CommandLine|contains:
            - ' -windowstyle h '
            - ' -windowstyl h'
            - ' -windowsty h'
            - ' -windowst h'
            - ' -windows h'
            - ' -windo h'
            - ' -wind h'
            - ' -win h'
            - ' -wi h'
            - ' -win h '
            - ' -win hi '
            - ' -win hid '
            - ' -win hidd '
            - ' -win hidde '
            - ' -NoPr '
            - ' -NoPro '
            - ' -NoProf '
            - ' -NoProfi '
            - ' -NoProfil '
            - ' -nonin '
            - ' -nonint '
            - ' -noninte '
            - ' -noninter '
            - ' -nonintera '
            - ' -noninterac '
            - ' -noninteract '
            - ' -noninteracti '
            - ' -noninteractiv '
            - ' -ec '
            - ' -encodedComman '
            - ' -encodedComma '
            - ' -encodedComm '
            - ' -encodedCom '
            - ' -encodedCo '
            - ' -encodedC '
            - ' -encoded '
            - ' -encode '
            - ' -encod '
            - ' -enco '
            - ' -en '
            - ' -executionpolic '
            - ' -executionpoli '
            - ' -executionpol '
            - ' -executionpo '
            - ' -executionp '
            - ' -execution bypass'
            - ' -executio bypass'
            - ' -executi bypass'
            - ' -execut bypass'
            - ' -execu bypass'
            - ' -exec bypass'
            - ' -exe bypass'
            - ' -ex bypass'
            - ' -ep bypass'
            - ' /windowstyle h '
            - ' /windowstyl h'
            - ' /windowsty h'
            - ' /windowst h'
            - ' /windows h'
            - ' /windo h'
            - ' /wind h'
            - ' /win h'
            - ' /wi h'
            - ' /win h '
            - ' /win hi '
            - ' /win hid '
            - ' /win hidd '
            - ' /win hidde '
            - ' /NoPr '
            - ' /NoPro '
            - ' /NoProf '
            - ' /NoProfi '
            - ' /NoProfil '
            - ' /nonin '
            - ' /nonint '
            - ' /noninte '
            - ' /noninter '
            - ' /nonintera '
            - ' /noninterac '
            - ' /noninteract '
            - ' /noninteracti '
            - ' /noninteractiv '
            - ' /ec '
            - ' /encodedComman '
            - ' /encodedComma '
            - ' /encodedComm '
            - ' /encodedCom '
            - ' /encodedCo '
            - ' /encodedC '
            - ' /encoded '
            - ' /encode '
            - ' /encod '
            - ' /enco '
            - ' /en '
            - ' /executionpolic '
            - ' /executionpoli '
            - ' /executionpol '
            - ' /executionpo '
            - ' /executionp '
            - ' /execution bypass'
            - ' /executio bypass'
            - ' /executi bypass'
            - ' /execut bypass'
            - ' /execu bypass'
            - ' /exec bypass'
            - ' /exe bypass'
            - ' /ex bypass'
            - ' /ep bypass'
    condition: selection