{"id":"f17211f1-1f24-4d0c-829f-31e28dc93cdd","title":"Uncommon Svchost Command Line Parameter","description":"Detects instances of svchost.exe running with an unusual or uncommon command line parameter by excluding known legitimate or common patterns.\nThis could point at a file masquerading as svchost, a process injection, or hollowing of a legitimate svchost instance.\n","author":"Liran Ravich","status":"experimental","level":"high","date":"2025-11-14","modified":"2026-03-23","tags":["attack.privilege-escalation","attack.stealth","attack.t1036.005","attack.t1055","attack.t1055.012"],"technique_ids":["T1036.005","T1055","T1055.012"],"logsource":{"category":"process_creation","product":"windows"},"falsepositives":["Unlikely"],"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"],"source_path":"rules/windows/process_creation/proc_creation_win_svchost_uncommon_command_line_flags.yml","source_sha256":"1b968ee4fd072ec498b783dd4f48314f6b9c5bd9e3ad83abe3bfe73a53f606d4","source_url":"https://github.com/anpa1200/sigma/blob/b249e9683190cffdcaf188ccbfb90bf4759844e1/rules/windows/process_creation/proc_creation_win_svchost_uncommon_command_line_flags.yml","license":"Detection Rule License 1.1","license_url":"https://github.com/SigmaHQ/Detection-Rule-License/blob/main/LICENSE.Detection.Rules.md","yaml":"title: Uncommon Svchost Command Line Parameter\nid: f17211f1-1f24-4d0c-829f-31e28dc93cdd\nstatus: experimental\ndescription: |\n    Detects instances of svchost.exe running with an unusual or uncommon command line parameter by excluding known legitimate or common patterns.\n    This could point at a file masquerading as svchost, a process injection, or hollowing of a legitimate svchost instance.\nreferences:\n    - https://cardinalops.com/blog/the-art-of-anomaly-hunting-patterns-detection/\n    - https://www.security.com/threat-intelligence/blackbyte-exbyte-ransomware\n    - https://cloud.google.com/blog/topics/threat-intelligence/apt41-initiates-global-intrusion-campaign-using-multiple-exploits/\n    - https://media.kasperskycontenthub.com/wp-content/uploads/sites/43/2018/03/08064518/Carbanak_APT_eng.pdf\nauthor: Liran Ravich\ndate: 2025-11-14\nmodified: 2026-03-23\ntags:\n    - attack.privilege-escalation\n    - attack.stealth\n    - attack.t1036.005\n    - attack.t1055\n    - attack.t1055.012\nlogsource:\n    category: process_creation\n    product: windows\ndetection:\n    selection:\n        # Example of command to simulate: \"C:\\Windows\\System32\\svchost.exe\" calc.exe\n        Image|endswith: '\\svchost.exe'\n    filter_main_flags:\n        CommandLine|re: '-k\\s\\w{1,64}(?:\\s?(?:-p|-s))?'\n    filter_main_empty:\n        CommandLine: ''\n    filter_main_null:\n        CommandLine: null\n    filter_optional_defender:\n        ParentImage|endswith: '\\MsMpEng.exe'\n        CommandLine|contains: 'svchost.exe'\n    filter_optional_mrt:\n        ParentImage|endswith: '\\MRT.exe'\n        CommandLine: 'svchost.exe'\n    condition: selection and not 1 of filter_main_* and not 1 of filter_optional_*\nfalsepositives:\n    - Unlikely\nlevel: high\n","validation":"yaml_parsed_not_backend_compiled_or_live_validated","techniques":[{"key":"enterprise/T1036.005","id":"T1036.005","name":"Match Legitimate Resource Name or Location","page":"techniques/enterprise/T1036.005/"},{"key":"enterprise/T1055","id":"T1055","name":"Process Injection","page":"techniques/enterprise/T1055/"},{"key":"enterprise/T1055.012","id":"T1055.012","name":"Process Hollowing","page":"techniques/enterprise/T1055.012/"}],"data_path":"data/detection-rules/f17211f1-1f24-4d0c-829f-31e28dc93cdd.json","kind":"sigma"}