Detection: Windows AD DSRM Account Changes

Description

The following analytic identifies changes to the Directory Services Restore Mode (DSRM) account behavior via registry modifications. It detects alterations in the registry path "*\System\CurrentControlSet\Control\Lsa\DSRMAdminLogonBehavior" with specific values indicating potential misuse. This activity is significant because the DSRM account, if misconfigured, can be exploited to persist within a domain, similar to a local administrator account. If confirmed malicious, an attacker could gain persistent administrative access to a Domain Controller, leading to potential domain-wide compromise and unauthorized access to sensitive information.

Search

1
2| tstats `security_content_summariesonly` min(_time) as _time from datamodel=Endpoint.Registry where Registry.registry_path= "*\\System\\CurrentControlSet\\Control\\Lsa\\DSRMAdminLogonBehavior" Registry.registry_value_data IN ("*1","*2") by Registry.action Registry.registry_path Registry.registry_value_data Registry.registry_value_type Registry.process_guid Registry.dest Registry.user 
3| `drop_dm_object_name(Registry)` 
4| join type=outer process_guid [
5| 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 
6| `drop_dm_object_name(Processes)`] 
7| table _time action dest user parent_process_name parent_process process_name process process_guid registry_path registry_value_data registry_value_type 
8| `windows_ad_dsrm_account_changes_filter`

Data Source

Name	Platform	Sourcetype	Source	Supported App
Sysmon EventID 1	Windows	'xmlwineventlog'	'XmlWinEventLog:Microsoft-Windows-Sysmon/Operational'	N/A

Macros Used

Annotations

Default Configuration

This detection is configured by default in Splunk Enterprise Security to run with the following settings:

Implementation

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

Disaster recovery events.

Associated Analytic Story

• Sneaky Active Directory Persistence Tricks

• Windows Persistence Techniques

• Windows Registry Abuse

Risk Based Analytics (RBA)

References

• https://adsecurity.org/?p=1714

Detection Testing

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

Source: GitHub | Version: 3