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: 2025-12-03
10tags:
11    - attack.privilege-escalation
12    - attack.persistence
13    - attack.execution
14    - attack.stealth
15    - attack.t1574.001
16logsource:
17    product: windows
18    category: file_event
19detection:
20    selection:
21        TargetFilename|endswith:
22            - '\WerFault.exe'
23            - '\wer.dll'
24    filter_main_known_locations:
25        TargetFilename|startswith:
26            - 'C:\Windows\SoftwareDistribution\'
27            - 'C:\Windows\System32\'
28            - 'C:\Windows\SysWOW64\'
29            - 'C:\Windows\WinSxS\'
30            - 'C:\Windows\UUS\arm64\'
31    condition: selection and not 1 of filter_main_*
32falsepositives:
33    - Unknown
34level: medium