Detection: Windows System LogOff Commandline

Description

The following analytic detects the execution of the Windows command line to log off a host machine. It leverages data from Endpoint Detection and Response (EDR) agents, focusing on processes involving shutdown.exe with specific parameters. This activity is significant as it is often associated with Advanced Persistent Threats (APTs) and Remote Access Trojans (RATs) like dcrat, which use this technique to disrupt operations, aid in system destruction, or inhibit recovery. If confirmed malicious, this could lead to system downtime, data loss, or hindered incident response efforts.

Search

1
2| tstats `security_content_summariesonly` values(Processes.process) as process min(_time) as firstTime max(_time) as lastTime from datamodel=Endpoint.Processes where (Processes.process_name = shutdown.exe OR Processes.original_file_name = shutdown.exe) Processes.process="*shutdown*" Processes.process IN ("* /l*", "* -l*") Processes.process IN ("* /t*","* -t*","* /f*","* -f*") by Processes.dest Processes.user Processes.parent_process Processes.process_name Processes.original_file_name Processes.process Processes.process_id Processes.parent_process_id 
3| `drop_dm_object_name(Processes)` 
4| `security_content_ctime(firstTime)` 
5| `security_content_ctime(lastTime)` 
6| `windows_system_logoff_commandline_filter`

Data Source

Name	Platform	Sourcetype	Source
CrowdStrike ProcessRollup2	N/A	'crowdstrike:events:sensor'	'crowdstrike'
Sysmon EventID 1	Windows	'xmlwineventlog'	'XmlWinEventLog:Microsoft-Windows-Sysmon/Operational'
Windows Event Log Security 4688	Windows	'xmlwineventlog'	'XmlWinEventLog:Security'

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

Administrator may execute this commandline to trigger shutdown, logoff or restart the host machine.

Associated Analytic Story

• DarkCrystal RAT

• NjRAT

Risk Based Analytics (RBA)

References

• https://attack.mitre.org/techniques/T1529/

• https://www.mandiant.com/resources/analyzing-dark-crystal-rat-backdoor

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