Fsutil Suspicious Invocation — Sigma Rule

Rule metadata and linked tags

Author: Ecco, E.M. Anhaus, oscd.community. Source status: stable; severity: high. Source dates: 2019-09-26 / 2023-09-09.

{
  "category": "process_creation",
  "product": "windows"
}

Pinned original Sigma rule · Detection Rule License 1.1

Source SHA-256: 81cd99db0548c5dc4de9cc98f5800809ef6437c16c76ee6e1c1711f6a6c8ff93

Detection logic

Original source YAML. Source-tag agreement is not proof of complete semantic coverage. This rule has not been compiled for a SIEM backend or validated against live telemetry here.

title: Fsutil Suspicious Invocation
id: add64136-62e5-48ea-807e-88638d02df1e
status: stable
description: |
  Detects suspicious parameters of fsutil (deleting USN journal, configuring it with small size, etc).
  Might be used by ransomwares during the attack (seen by NotPetya and others).
references:
    - https://learn.microsoft.com/en-us/windows-server/administration/windows-commands/fsutil-usn
    - https://github.com/redcanaryco/atomic-red-team/blob/f339e7da7d05f6057fdfcdd3742bfcf365fee2a9/atomics/T1070/T1070.md
    - https://eqllib.readthedocs.io/en/latest/analytics/c91f422a-5214-4b17-8664-c5fcf115c0a2.html
    - https://github.com/albertzsigovits/malware-notes/blob/558898932c1579ff589290092a2c8febefc3a4c9/Ransomware/Lockbit.md
    - https://blog.cluster25.duskrise.com/2023/05/22/back-in-black-blackbyte-nt
author: Ecco, E.M. Anhaus, oscd.community
date: 2019-09-26
modified: 2023-09-09
tags:
    - attack.impact
    - attack.stealth
    - attack.t1070
    - attack.t1485
logsource:
    category: process_creation
    product: windows
detection:
    selection_img:
        - Image|endswith: '\fsutil.exe'
        - OriginalFileName: 'fsutil.exe'
    selection_cli:
        CommandLine|contains:
            - 'deletejournal'        # usn deletejournal ==> generally ransomware or attacker
            - 'createjournal'        # usn createjournal ==> can modify config to set it to a tiny size
            - 'setZeroData'          # file setZeroData  ==> empties a file with zeroes
    condition: all of selection_*
falsepositives:
    - Admin activity
    - Scripts and administrative tools used in the monitored environment
level: high

Original YAML and metadata in JSON

False positives

• Admin activity
• Scripts and administrative tools used in the monitored environment

Source references

• https://learn.microsoft.com/en-us/windows-server/administration/windows-commands/fsutil-usn
• https://github.com/redcanaryco/atomic-red-team/blob/f339e7da7d05f6057fdfcdd3742bfcf365fee2a9/atomics/T1070/T1070.md
• https://eqllib.readthedocs.io/en/latest/analytics/c91f422a-5214-4b17-8664-c5fcf115c0a2.html
• https://github.com/albertzsigovits/malware-notes/blob/558898932c1579ff589290092a2c8febefc3a4c9/Ransomware/Lockbit.md
• https://blog.cluster25.duskrise.com/2023/05/22/back-in-black-blackbyte-nt