Windows BitLocker Suspicious Command Usage

SPLUNK detection rule by Steven Dick · Apache-2.0

This analytic is developed to detect the usage of BitLocker commands used to disable or impact boot settings. The malware ShrinkLocker uses various commands change how BitLocker handles encryption, potentially bypassing TPM requirements, enabling BitLocker without TPM, and enforcing specific startup key and PIN configurations. Such modifications can weaken system security, making it easier for unauthorized access and data breaches. Detecting these changes is crucial for maintaining robust encryption and data protection.

name: Windows BitLocker Suspicious Command Usage
id: d0e6ec70-6e40-41a2-8b93-8d9ff077a746
version: 7
creation_date: '2025-02-10'
modification_date: '2026-05-13'
author: Steven Dick
status: production
type: TTP
description: This analytic is developed to detect the usage of BitLocker commands used to disable or impact boot settings. The malware ShrinkLocker uses various commands change how BitLocker handles encryption, potentially bypassing TPM requirements, enabling BitLocker without TPM, and enforcing specific startup key and PIN configurations. Such modifications can weaken system security, making it easier for unauthorized access and data breaches. Detecting these changes is crucial for maintaining robust encryption and data protection.
data_source:
    - Sysmon EventID 1
    - Windows Event Log Security 4688
    - CrowdStrike ProcessRollup2
search: |-
    | tstats `security_content_summariesonly` min(_time) as firstTime max(_time) as lastTime FROM datamodel=Endpoint.Processes
      WHERE Processes.process_name = manage-bde.exe
        AND
        Processes.process IN ("* -protectors -disable *","* -protectors -delete *","* -forcerecovery *","* -lock *")
      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)`
    | `windows_bitlocker_suspicious_command_usage_filter`
how_to_implement: To successfully implement this search you need to be ingesting information on process that include the name of the process responsible for the changes from your endpoints into the `Endpoint` datamodel in the `Processes` node. In addition, confirm the latest CIM App 4.20 or higher is installed and the latest TA for the endpoint product.
known_false_positives: Administrators may enable or disable this feature that may cause some false positive.
references:
    - https://attack.mitre.org/techniques/T1486/
    - https://www.nccgroup.com/us/research-blog/nameless-and-shameless-ransomware-encryption-via-bitlocker/
    - https://www.bitdefender.com/en-us/blog/businessinsights/shrinklocker-decryptor-from-friend-to-foe-and-back-again
    - https://www.bleepingcomputer.com/news/security/new-shrinklocker-ransomware-uses-bitlocker-to-encrypt-your-files/
drilldown_searches:
    - name: View the detection results for - "$dest$" and "$user$"
      search: '%original_detection_search% | search dest = "$dest$" user = "$user$"'
      earliest_offset: $info_min_time$
      latest_offset: $info_max_time$
    - name: View risk events for the last 7 days for - "$dest$" and "$user$"
      search: '| from datamodel Risk.All_Risk | search normalized_risk_object IN ("$dest$","$user$") | stats count min(_time) as firstTime max(_time) as lastTime values(search_name) as "Search Name" values(risk_message) as "Risk Message" values(analyticstories) as "Analytic Stories" values(annotations._all) as "Annotations" values(annotations.mitre_attack.mitre_tactic) as "ATT&CK Tactics" by normalized_risk_object | `security_content_ctime(firstTime)` | `security_content_ctime(lastTime)`'
      earliest_offset: 7d
      latest_offset: "0"
    - name: Investigate processes on $dest$
      search: '| from datamodel Endpoint.Processes | search process_name = $process_name$ AND dest = "$dest$"'
      earliest_offset: $info_min_time$
      latest_offset: $info_max_time$
finding:
    title: A suspicious Windows BitLocker command was run by $user$ detected on $dest$
    entity:
        field: user
        type: user
        score: 50
intermediate_findings:
    entities:
        - field: dest
          type: system
          score: 50
          message: A suspicious Windows BitLocker command was run by $user$ detected on $dest$
threat_objects:
    - field: parent_process
      type: process
analytic_story:
    - ShrinkLocker
asset_type: Endpoint
mitre_attack_id:
    - T1486
    - T1490
product:
    - Splunk Enterprise
    - Splunk Enterprise Security
    - Splunk Cloud
category: endpoint
security_domain: endpoint
tests:
    - name: True Positive Test
      attack_data:
        - data: https://media.githubusercontent.com/media/splunk/attack_data/master/datasets/attack_techniques/T1486/bitlocker_sus_commands/bitlocker_sus_commands.log
          source: XmlWinEventLog:Microsoft-Windows-Sysmon/Operational
          sourcetype: XmlWinEventLog
      test_type: unit

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