Detection: Windows Remote Management Execute Shell

Description

The following analytic detects the execution of winrshost.exe initiating CMD or PowerShell processes as part of a potential payload execution. winrshost.exe is associated with Windows Remote Management (WinRM) and is typically used for remote execution. By monitoring for this behavior, the detection identifies instances where winrshost.exe is leveraged to run potentially malicious commands or payloads via CMD or PowerShell. This behavior may indicate exploitation of remote management tools for unauthorized access or lateral movement within a compromised environment, signaling a potential security incident.

Search

1
2| tstats `security_content_summariesonly` min(_time) as firstTime max(_time) as lastTime from datamodel=Endpoint.Processes where Processes.parent_process_name="winrshost.exe" AND Processes.process_name IN ("cmd.exe","*powershell*") by Processes.parent_process_name Processes.parent_process Processes.process_name Processes.process Processes.process_guid Processes.dest Processes.user 
3| `drop_dm_object_name(Processes)` 
4| `security_content_ctime(firstTime)` 
5| `security_content_ctime(lastTime)` 
6| `windows_remote_management_execute_shell_filter`

Data Source

Name	Platform	Sourcetype	Source
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 or power user can execute command shell or script remotely using WINRM.

Associated Analytic Story

• Crypto Stealer

Risk Based Analytics (RBA)

Risk Message:

a winrm remote proces [$parent_process_name$] execute [$process_name$] shell on [$dest$].

References

• https://strontic.github.io/xcyclopedia/library/winrshost.exe-6790044CEB4BA5BE6AA8161460D990FD.html

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: 1