{"id":"50919691-7302-437f-8e10-1fe088afa145","title":"Regsvr32 DLL Execution With Uncommon Extension","description":"Detects a \"regsvr32\" execution where the DLL doesn't contain a common file extension.","author":"Florian Roth (Nextron Systems)","status":"test","level":"medium","date":"2019-07-17","modified":"2023-05-24","tags":["attack.privilege-escalation","attack.persistence","attack.stealth","attack.t1574","attack.execution"],"technique_ids":["T1574"],"logsource":{"category":"process_creation","product":"windows"},"falsepositives":["Other legitimate extensions currently not in the list either from third party or specific Windows components."],"references":["https://app.any.run/tasks/34221348-072d-4b70-93f3-aa71f6ebecad/"],"source_path":"rules/windows/process_creation/proc_creation_win_regsvr32_uncommon_extension.yml","source_sha256":"cd29b26a554375e196f296f0b051228a1c84f8057e42ee3e4159da43a6c70b16","source_url":"https://github.com/anpa1200/sigma/blob/b249e9683190cffdcaf188ccbfb90bf4759844e1/rules/windows/process_creation/proc_creation_win_regsvr32_uncommon_extension.yml","license":"Detection Rule License 1.1","license_url":"https://github.com/SigmaHQ/Detection-Rule-License/blob/main/LICENSE.Detection.Rules.md","yaml":"title: Regsvr32 DLL Execution With Uncommon Extension\nid: 50919691-7302-437f-8e10-1fe088afa145\nstatus: test\ndescription: Detects a \"regsvr32\" execution where the DLL doesn't contain a common file extension.\nreferences:\n    - https://app.any.run/tasks/34221348-072d-4b70-93f3-aa71f6ebecad/\nauthor: Florian Roth (Nextron Systems)\ndate: 2019-07-17\nmodified: 2023-05-24\ntags:\n    - attack.privilege-escalation\n    - attack.persistence\n    - attack.stealth\n    - attack.t1574\n    - attack.execution\nlogsource:\n    category: process_creation\n    product: windows\ndetection:\n    selection:\n        - Image|endswith: '\\regsvr32.exe'\n        - OriginalFileName: 'REGSVR32.EXE'\n    filter_main_legit_ext:\n        CommandLine|contains:\n            # Note: For better accuracy you might not want to use contains\n            - '.ax'\n            - '.cpl'\n            - '.dll' # Covers \".dll.mui\"\n            - '.ocx'\n    filter_optional_pascal:\n        CommandLine|contains: '.ppl'\n    filter_optional_avg:\n        CommandLine|contains: '.bav'\n    filter_main_null_4688:\n        CommandLine: null\n    filter_main_empty_4688:\n        CommandLine: ''\n    condition: selection and not 1 of filter_main_* and not 1 of filter_optional_*\nfalsepositives:\n    - Other legitimate extensions currently not in the list either from third party or specific Windows components.\nlevel: medium\n","validation":"yaml_parsed_not_backend_compiled_or_live_validated","techniques":[{"key":"enterprise/T1574","id":"T1574","name":"Hijack Execution Flow","page":"techniques/enterprise/T1574/"}],"data_path":"data/detection-rules/50919691-7302-437f-8e10-1fe088afa145.json","kind":"sigma"}