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Description

This detection looks for the deletion of registry keys which disable LSA protection and MS Defender Device Guard.

  • Type: TTP
  • Product: Splunk Enterprise, Splunk Enterprise Security, Splunk Cloud
  • Datamodel: Endpoint
  • Last Updated: 2022-09-09
  • Author: Dean Luxton
  • ID: 45cd08f8-a2c9-4f4e-baab-e1a0c624b0ab

Annotations

ATT&CK

ATT&CK

ID Technique Tactic
T1556 Modify Authentication Process Credential Access, Defense Evasion, Persistence
Kill Chain Phase
  • Actions on Objectives
NIST
  • DE.CM
CIS20
  • CIS 5
  • CIS 6
  • CIS 16
CVE 


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| tstats `security_content_summariesonly` min(_time) as _time from datamodel=Endpoint.Registry where Registry.registry_path IN ("*\\SYSTEM\\CurrentControlSet\\Control\\Lsa\\LsaCfgFlags", "*\\SOFTWARE\\Policies\\Microsoft\\Windows\\DeviceGuard\\*", "*\\SYSTEM\\CurrentControlSet\\Control\\Lsa\\RunAsPPL") Registry.action IN (deleted, unknown) by Registry.action Registry.registry_path Registry.process_guid 
| `drop_dm_object_name(Registry)` 
| join type=outer process_guid [
| tstats `security_content_summariesonly` count FROM datamodel=Endpoint.Processes by Processes.user Processes.process_name Processes.process Processes.dest Processes.parent_process_name Processes.parent_process Processes.process_guid 
| `drop_dm_object_name(Processes)`] 
| table _time action dest user parent_process_name parent_process process_name process process_guid registry_path 
| `disabling_windows_local_security_authority_defences_via_registry_filter`

Macros

The SPL above uses the following Macros:

:information_source: disabling_windows_local_security_authority_defences_via_registry_filter is a empty macro by default. It allows the user to filter out any results (false positives) without editing the SPL.

Required fields

List of fields required to use this analytic.

  • _time
  • Registry.action
  • Registry.registry_path
  • Registry.dest
  • Registry.user

How To Implement

To successfully implement this search, you must be ingesting data that records registry activity from your hosts to populate the endpoint data model in the registry node. This is typically populated via endpoint detection-and-response product, such as Carbon Black or endpoint data sources, such as Sysmon. The data used for this search is typically generated via logs that report reads and writes to the registry.

Known False Positives

Potential to be triggered by an administrator disabling protections for troubleshooting purposes.

Associated Analytic Story

RBA

Risk Score Impact Confidence Message
60.0 60 100 An attempt to disable Windows LSA defences was detected on $dest$. The reg key $registry_path$ was deleted by $user$.

:information_source: The Risk Score is calculated by the following formula: Risk Score = (Impact * Confidence/100). Initial Confidence and Impact is set by the analytic author.

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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