Sigma rule: Clfs.SYS Loaded By Process Located In a Potential Suspicious Location

Rule

Title

Clfs.SYS Loaded By Process Located In a Potential Suspicious Location

Status

experimental

Level

medium

Author

X__Junior

Date

2025-01-20

File

rules/windows/image_load/image_load_clfs_load.yml

Commit

ccbb0369507f796db0b0ae6854c8a2be471b9d84

Detects Clfs.sys being loaded by a process running from a potentially suspicious location. Clfs.sys is loaded as part of many CVEs exploits that targets Common Log File.

Log source

product

windows

category

image_load

Detection

selection_dll:
    ImageLoaded|endswith: '\clfs.sys'
selection_folders_1:
    Image|contains:
        - ':\Perflogs\'
        - ':\Users\Public\'
        - '\Temporary Internet'
        - '\Windows\Temp\'
selection_folders_2:
    - Image|contains|all:
          - ':\Users\'
          - '\Favorites\'
    - Image|contains|all:
          - ':\Users\'
          - '\Favourites\'
    - Image|contains|all:
          - ':\Users\'
          - '\Contacts\'
    - Image|contains|all:
          - ':\Users\'
          - '\Pictures\'
condition: selection_dll and 1 of selection_folders_*

False positives (as the rule lists them)

• Unknown

Tags

• attack.execution
• attack.t1059

MITRE ATT&CK ids this rule names

• T1059

References

• https://ssd-disclosure.com/ssd-advisory-common-log-file-system-clfs-driver-pe/
• https://x.com/Threatlabz/status/1879956781360976155

Read on 2026-11-03T00:58:21.399Z under licence sigma-drl-1.1@d5f4c36a from https://github.com/SigmaHQ/sigma/blob/ccbb0369507f796db0b0ae6854c8a2be471b9d84/rules/windows/image_load/image_load_clfs_load.yml