Detectionmediumexperimental

Suspicious Cross-User Process Spawn

Detects suspicious spawning of a process under a different user context than the parent process. Processes such as notepad.exe, calculator etc. are generally spawned under the same user context and also they are often targeted as sacrificial process or decoy process to check successful privilege escalation.

Convert In Phoenix Studio

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

Launch

Swachchhanda Shrawan Poudel (Nextron Systems)Created Thu Jul 23d2b7a134-9c3e-4f8a-b56d-e0c1f8a29b47windows

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:
            - '\notepad.exe'
            - '\calc.exe'
            - '\mspaint.exe'
            - '\wordpad.exe'
            - '\write.exe'
    filter_main_same_user:
        User|fieldref: ParentUser
    filter_optional_user_null:
        User: null
    filter_optional_parent_null:
        ParentUser: null
    filter_optional_empty_user:
        - ParentUser:
              - ''
              - '-'
        - User:
              - ''
              - '-'
    condition: selection and not 1 of filter_main_* and not 1 of filter_optional_*