Detection rules › Splunk

USN Journal Deletion

Status
production
Severity
medium
Group by
IntegrityLevel, command_line, computer_name, event_action, original_file_name, parent_command_line, parent_process_guid, parent_process_id, parent_process_name, process_guid, process_hash, process_id, process_name, user, user_id, vendor_product
Author
David Dorsey, Splunk
Source
github.com/splunk/security_content

The following analytic detects the deletion of the USN Journal using the fsutil.exe utility. It leverages data from Endpoint Detection and Response (EDR) agents, focusing on process execution logs that include command-line details. This activity is significant because the USN Journal maintains a log of all changes made to files on the disk, and its deletion can be an indicator of an attempt to cover tracks or hinder forensic investigations. If confirmed malicious, this action could allow an attacker to obscure their activities, making it difficult to trace file modifications and potentially compromising incident response efforts.

Known false positives

  • No false positives have been identified at this time.

MITRE ATT&CK coverage

TacticTechniques
Stealth

Telemetry coverage

Rule body

name: USN Journal Deletion
id: b6e0ff70-b122-4227-9368-4cf322ab43c3
version: 13
creation_date: '2020-04-29'
modification_date: '2026-05-13'
author: David Dorsey, Splunk
status: production
type: TTP
description: The following analytic detects the deletion of the USN Journal using the fsutil.exe utility. It leverages data from Endpoint Detection and Response (EDR) agents, focusing on process execution logs that include command-line details. This activity is significant because the USN Journal maintains a log of all changes made to files on the disk, and its deletion can be an indicator of an attempt to cover tracks or hinder forensic investigations. If confirmed malicious, this action could allow an attacker to obscure their activities, making it difficult to trace file modifications and potentially compromising incident response efforts.
data_source:
    - Sysmon EventID 1
    - Windows Event Log Security 4688
    - CrowdStrike ProcessRollup2
search: |
    | tstats `security_content_summariesonly`
      count values(Processes.process) as process
            values(Processes.parent_process) as parent_process
            min(_time) as firstTime
            max(_time) as lastTime
    
    from datamodel=Endpoint.Processes where
    
    Processes.process_name=fsutil.exe
    Processes.process = "*usn*"
    Processes.process = "*deletejournal*"
    
    by Processes.action Processes.dest Processes.original_file_name Processes.parent_process
       Processes.parent_process_exec Processes.parent_process_guid Processes.parent_process_id
       Processes.parent_process_name Processes.parent_process_path Processes.process Processes.process_exec
       Processes.process_guid Processes.process_hash Processes.process_id Processes.process_integrity_level
       Processes.process_name Processes.process_path Processes.user Processes.user_id Processes.vendor_product
    
    | `drop_dm_object_name(Processes)`
    | `security_content_ctime(firstTime)`
    | `security_content_ctime(lastTime)`
    | `usn_journal_deletion_filter`
how_to_implement: The detection is based on data that originates from Endpoint Detection and Response (EDR) agents. These agents are designed to provide security-related telemetry from the endpoints where the agent is installed. To implement this search, you must ingest logs that contain the process GUID, process name, and parent process. Additionally, you must ingest complete command-line executions. These logs must be processed using the appropriate Splunk Technology Add-ons that are specific to the EDR product. The logs must also be mapped to the `Processes` node of the `Endpoint` data model. Use the Splunk Common Information Model (CIM) to normalize the field names and speed up the data modeling process.
known_false_positives: No false positives have been identified at this time.
references:
    - https://learn.microsoft.com/en-us/windows-server/administration/windows-commands/fsutil-usn
finding:
    title: Possible USN journal deletion on $dest$ via $process$
    entity:
        field: dest
        type: system
        score: 50
analytic_story:
    - Windows Log Manipulation
    - Ransomware
asset_type: Endpoint
mitre_attack_id:
    - T1070
product:
    - Splunk Enterprise
    - Splunk Enterprise Security
    - Splunk Cloud
category: endpoint
security_domain: endpoint

Stages and Predicates

Stage 1: tstats

| tstats `security_content_summariesonly`
  count values(Processes.process) as process
        values(Processes.parent_process) as parent_process
        min(_time) as firstTime
        max(_time) as lastTime

from datamodel=Endpoint.Processes where

Processes.process_name=fsutil.exe
Processes.process = "*usn*"
Processes.process = "*deletejournal*"

by Processes.action Processes.dest Processes.original_file_name Processes.parent_process
   Processes.parent_process_exec Processes.parent_process_guid Processes.parent_process_id
   Processes.parent_process_name Processes.parent_process_path Processes.process Processes.process_exec
   Processes.process_guid Processes.process_hash Processes.process_id Processes.process_integrity_level
   Processes.process_name Processes.process_path Processes.user Processes.user_id Processes.vendor_product

Stage 2: search

| `drop_dm_object_name(Processes)`

Stage 3: search

| `security_content_ctime(firstTime)`

Stage 4: search

| `security_content_ctime(lastTime)`

Stage 5: search

| `usn_journal_deletion_filter`

Indicators

These rows show field, operator, and value matches.

FieldKindValuesSearch
Processes.processeq
  • "*deletejournal*" corpus 2 (sigma 1, splunk 1)
  • "*usn*"
field:"CommandLine" kind:eq
Processes.process_nameeq
  • "fsutil.exe" corpus 7 (splunk 4, elastic 3)
field:"process_name" kind:eq