Detection: Detect Use of cmd exe to Launch Script Interpreters

Description

The following analytic detects the execution of cscript.exe or wscript.exe processes initiated by cmd.exe. It leverages data from Endpoint Detection and Response (EDR) agents, focusing on process names and parent processes within the Endpoint data model. This activity is significant as it may indicate script-based attacks or administrative actions that could be leveraged for malicious purposes. If confirmed malicious, this behavior could allow attackers to execute scripts, potentially leading to code execution, privilege escalation, or persistence within the environment.

Search

1
2| tstats `security_content_summariesonly` count min(_time) as firstTime max(_time) as lastTime from datamodel=Endpoint.Processes where Processes.parent_process_name="cmd.exe" (Processes.process_name=cscript.exe OR Processes.process_name =wscript.exe) by Processes.parent_process Processes.process_name Processes.process Processes.user Processes.dest 
3| `drop_dm_object_name("Processes")` 
4| `security_content_ctime(firstTime)`
5|`security_content_ctime(lastTime)` 
6| `detect_use_of_cmd_exe_to_launch_script_interpreters_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

This detection may also be triggered by legitimate applications and numerous service accounts, which often end with a $ sign. To manage this, it's advised to check the service account's activities and, if they are valid, modify the filter macro to exclude them.

Associated Analytic Story

• Azorult

• Emotet Malware DHS Report TA18-201A

• Suspicious Command-Line Executions

Risk Based Analytics (RBA)

References

• https://attack.mitre.org/techniques/T1059/

• https://redcanary.com/threat-detection-report/techniques/windows-command-shell/

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: 7