Detection: Script Execution via WMI

Description

The following analytic detects the execution of scripts via Windows Management Instrumentation (WMI) by monitoring the process 'scrcons.exe'. This detection leverages data from Endpoint Detection and Response (EDR) agents, focusing on process creation events. WMI-based script execution is significant because adversaries often use it to perform malicious activities stealthily, such as system compromise, data exfiltration, or establishing persistence. If confirmed malicious, this activity could allow attackers to execute arbitrary code, escalate privileges, or maintain long-term access to the environment. Analysts should differentiate between legitimate administrative use and potential threats.

Search

1
2| tstats `security_content_summariesonly` count min(_time) as firstTime max(_time) as lastTime from datamodel=Endpoint.Processes where Processes.process_name=scrcons.exe by Processes.action Processes.dest Processes.original_file_name Processes.parent_process Processes.parent_process_exec Processes.parent_process_guid Processes.parent_process_id Processes.parent_process_name Processes.parent_process_path Processes.process Processes.process_exec Processes.process_guid Processes.process_hash Processes.process_id Processes.process_integrity_level Processes.process_name Processes.process_path Processes.user Processes.user_id Processes.vendor_product 
3| `drop_dm_object_name(Processes)` 
4| `security_content_ctime(firstTime)` 
5| `security_content_ctime(lastTime)` 
6| `script_execution_via_wmi_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

Although unlikely, administrators may use wmi to launch scripts for legitimate purposes. Filter as needed.

Associated Analytic Story

• Suspicious WMI Use

Risk Based Analytics (RBA)

Risk Message:

A wmic.exe process $process_name$ that execute script in host $dest$

References

• https://redcanary.com/blog/child-processes/

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: 8