{"id":"28a452f3-786c-4fd8-b8f2-bddbe9d616d1","title":"Creation of WerFault.exe/Wer.dll in Unusual Folder","description":"Detects the creation of a file named \"WerFault.exe\" or \"wer.dll\" in an uncommon folder, which could be a sign of WerFault DLL hijacking.","author":"frack113","status":"test","level":"medium","date":"2022-05-09","modified":"2026-05-18","tags":["attack.privilege-escalation","attack.persistence","attack.execution","attack.stealth","attack.t1574.001"],"technique_ids":["T1574.001"],"logsource":{"product":"windows","category":"file_event"},"falsepositives":["Unknown"],"references":["https://www.bleepingcomputer.com/news/security/hackers-are-now-hiding-malware-in-windows-event-logs/"],"source_path":"rules/windows/file/file_event/file_event_win_werfault_dll_hijacking.yml","source_sha256":"edc6a08b945eb5cd13101a2499395728a86d45e1bb4e9b010915aabb8f899dc8","source_url":"https://github.com/anpa1200/sigma/blob/b249e9683190cffdcaf188ccbfb90bf4759844e1/rules/windows/file/file_event/file_event_win_werfault_dll_hijacking.yml","license":"Detection Rule License 1.1","license_url":"https://github.com/SigmaHQ/Detection-Rule-License/blob/main/LICENSE.Detection.Rules.md","yaml":"title: Creation of WerFault.exe/Wer.dll in Unusual Folder\nid: 28a452f3-786c-4fd8-b8f2-bddbe9d616d1\nstatus: test\ndescription: Detects the creation of a file named \"WerFault.exe\" or \"wer.dll\" in an uncommon folder, which could be a sign of WerFault DLL hijacking.\nreferences:\n    - https://www.bleepingcomputer.com/news/security/hackers-are-now-hiding-malware-in-windows-event-logs/\nauthor: frack113\ndate: 2022-05-09\nmodified: 2026-05-18\ntags:\n    - attack.privilege-escalation\n    - attack.persistence\n    - attack.execution\n    - attack.stealth\n    - attack.t1574.001\nlogsource:\n    product: windows\n    category: file_event\ndetection:\n    selection:\n        TargetFilename|endswith:\n            - '\\WerFault.exe'\n            - '\\wer.dll'\n    filter_main_known_locations:\n        TargetFilename|startswith:\n            - 'C:\\Windows\\SoftwareDistribution\\'\n            - 'C:\\Windows\\System32\\'\n            - 'C:\\Windows\\SysWOW64\\'\n            - 'C:\\Windows\\WinSxS\\'\n            - 'C:\\Windows\\UUS\\' # covers both C:\\Windows\\UUS\\arm64\\ and C:\\Windows\\UUS\\packages\\\n    filter_main_process:\n        Image|endswith: '\\wuaucltcore.exe'\n    condition: selection and not 1 of filter_main_*\nfalsepositives:\n    - Unknown\nlevel: medium\n","validation":"yaml_parsed_not_backend_compiled_or_live_validated","techniques":[{"key":"enterprise/T1574.001","id":"T1574.001","name":"DLL","page":"techniques/enterprise/T1574.001/"}],"data_path":"data/detection-rules/28a452f3-786c-4fd8-b8f2-bddbe9d616d1.json","kind":"sigma"}