Fsutil Suspicious Invocation

01

description

What this is, in brief.

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).

02

rule source (YAML)

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
regression_tests_path: regression_data/rules/windows/process_creation/proc_creation_win_fsutil_usage/info.yml

04

detects techniques (2)

ATT&CK techniques this enables or maps to.

05

references

External citations — patches, advisories, analysis.