Detectionhightest

Suspicious Script Execution From Temp Folder

Detects a suspicious script executions from temporary folder

Convert In Phoenix Studio

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

Florian Roth (Nextron Systems), Max Altgelt (Nextron Systems), Tim SheltonCreated Wed Jul 14Updated Wed Oct 05a6a39bdb-935c-4f0a-ab77-35f4bbf44d33windows

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'
            - '\mshta.exe'
            - '\wscript.exe'
            - '\cscript.exe'
        CommandLine|contains:
            - '\Windows\Temp'
            - '\Temporary Internet'
            - '\AppData\Local\Temp'
            - '\AppData\Roaming\Temp'
            - '%TEMP%'
            - '%TMP%'
            - '%LocalAppData%\Temp'
    filter:
        CommandLine|contains:
            - ' >'
            - 'Out-File'
            - 'ConvertTo-Json'
            - '-WindowStyle hidden -Verb runAs'  # VSCode behaviour if file cannot be written as current user
            - '\Windows\system32\config\systemprofile\AppData\Local\Temp\Amazon\EC2-Windows\' # EC2 AWS
    condition: selection and not filter