Uncommon Svchost Command Line Parameter

title: Uncommon Svchost Command Line Parameter
id: f17211f1-1f24-4d0c-829f-31e28dc93cdd
status: experimental
description: |
    Detects instances of svchost.exe running with an unusual or uncommon command line parameter by excluding known legitimate or common patterns.
    This could point at a file masquerading as svchost, a process injection, or hollowing of a legitimate svchost instance.
references:
    - https://cardinalops.com/blog/the-art-of-anomaly-hunting-patterns-detection/
    - https://www.security.com/threat-intelligence/blackbyte-exbyte-ransomware
    - https://cloud.google.com/blog/topics/threat-intelligence/apt41-initiates-global-intrusion-campaign-using-multiple-exploits/
    - https://media.kasperskycontenthub.com/wp-content/uploads/sites/43/2018/03/08064518/Carbanak_APT_eng.pdf
author: Liran Ravich
date: 2025-11-14
tags:
    - attack.defense-evasion
    - attack.privilege-escalation
    - attack.t1036.005
    - attack.t1055
    - attack.t1055.012
logsource:
    category: process_creation
    product: windows
detection:
    selection:
        # Example of command to simulate: "C:\Windows\System32\svchost.exe" calc.exe
        Image|endswith: '\svchost.exe'
    filter_main_flags:
        CommandLine|re: '-k\s\w{1,64}(\s?(-p|-s))?'
    filter_main_empty:
        CommandLine: ''
    filter_main_null:
        CommandLine: null
    filter_optional_defender:
        ParentImage|endswith: '\MsMpEng.exe'
        CommandLine|contains: 'svchost.exe'
    filter_optional_mrt:
        ParentImage|endswith: '\MRT.exe'
        CommandLine: 'svchost.exe'
    condition: selection and not 1 of filter_main_* and not 1 of filter_optional_*
falsepositives:
    - Unlikely
level: high