Creation of WerFault.exe/Wer.dll in Unusual Folder

 1title: Creation of WerFault.exe/Wer.dll in Unusual Folder
 2id: 28a452f3-786c-4fd8-b8f2-bddbe9d616d1
 3status: test
 4description: 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.
 5references:
 6    - https://www.bleepingcomputer.com/news/security/hackers-are-now-hiding-malware-in-windows-event-logs/
 7author: frack113
 8date: 2022-05-09
 9modified: 2024-11-28
10tags:
11    - attack.persistence
12    - attack.defense-evasion
13    - attack.t1574.001
14logsource:
15    product: windows
16    category: file_event
17detection:
18    selection:
19        TargetFilename|endswith:
20            - '\WerFault.exe'
21            - '\wer.dll'
22    filter_main_known_locations:
23        TargetFilename|startswith:
24            - 'C:\Windows\SoftwareDistribution\'
25            - 'C:\Windows\System32\'
26            - 'C:\Windows\SysWOW64\'
27            - 'C:\Windows\WinSxS\'
28    condition: selection and not 1 of filter_main_*
29falsepositives:
30    - Unknown
31level: medium