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Description

This analytic is to detect a suspicious registry modification to disable Lock Computer windows features. This registry modification prevent the user from locking its screen or computer that are being abused by several malware for example ransomware. This technique was used by threat actor to make its payload more impactful to the compromised host.

  • Type: Anomaly
  • Product: Splunk Enterprise, Splunk Enterprise Security, Splunk Cloud
  • Datamodel: Endpoint
  • Last Updated: 2022-03-08
  • Author: Teoderick Contreras, Splunk
  • ID: c82adbc6-9f00-11ec-a81f-acde48001122

Annotations

ATT&CK
ID Technique Tactic
T1112 Modify Registry Defense Evasion
Kill Chain Phase
  • Exploitation
NIST
  • DE.CM
CIS20
  • CIS 3
  • CIS 5
  • CIS 16
CVE 
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| tstats `security_content_summariesonly` count from datamodel=Endpoint.Registry where Registry.registry_path= "*\\SOFTWARE\\Microsoft\\Windows\\CurrentVersion\\Policies\\System\\DisableLockWorkstation" Registry.registry_value_data = "0x00000001" by _time span=1h Registry.dest Registry.user Registry.registry_path Registry.registry_value_name Registry.registry_value_data Registry.process_guid 
| `drop_dm_object_name(Registry)` 
|rename process_guid as proc_guid 
|join proc_guid, _time [
| tstats `security_content_summariesonly` count FROM datamodel=Endpoint.Processes by _time span=1h Processes.process_id Processes.process_name Processes.process Processes.dest Processes.parent_process_name Processes.parent_process Processes.process_guid 
| `drop_dm_object_name(Processes)` 
|rename process_guid as proc_guid 
| fields _time dest user parent_process_name parent_process process_name process_path process proc_guid registry_path registry_value_name registry_value_data] 
| table _time dest user parent_process_name parent_process process_name process_path process proc_guid registry_path registry_value_name registry_value_data 
| `windows_disable_lock_workstation_feature_through_registry_filter`

Macros

The SPL above uses the following Macros:

Note that windows_disable_lock_workstation_feature_through_registry_filter is a empty macro by default. It allows the user to filter out any results (false positives) without editing the SPL.

Required field

  • _time
  • Registry.registry_key_name
  • Registry.registry_path
  • Registry.registry_value_name
  • Registry.dest Registry.user
  • Processes.process_id
  • Processes.process_name
  • Processes.process
  • Processes.dest
  • Processes.parent_process_name
  • Processes.parent_process
  • Processes.process_guid

How To Implement

To successfully implement this search you need to be ingesting information on process that include the name of the Filesystem responsible for the changes from your endpoints into the Endpoint datamodel in the Processes and Registry node.

Known False Positives

unknown

Associated Analytic story

RBA

Risk Score Impact Confidence Message
49.0 70 70 Registry modification in “DisableLockWorkstation” on $dest$

Reference

Test Dataset

Replay any dataset to Splunk Enterprise by using our replay.py tool or the UI. Alternatively you can replay a dataset into a Splunk Attack Range

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