Detection: Windows MSIExec Spawn WinDBG

Description

The following analytic identifies the unusual behavior of MSIExec spawning WinDBG. It detects this activity by analyzing endpoint telemetry data, specifically looking for instances where 'msiexec.exe' is the parent process of 'windbg.exe'. This behavior is significant as it may indicate an attempt to debug or tamper with system processes, which is uncommon in typical user activity and could signify malicious intent. If confirmed malicious, this activity could allow an attacker to manipulate or inspect running processes, potentially leading to 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=msiexec.exe Processes.process_name=windbg.exe by Processes.dest Processes.user Processes.parent_process_name Processes.parent_process_path Processes.parent_process Processes.process_name Processes.process_path 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_msiexec_spawn_windbg_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

False positives will only be present if the MSIExec process legitimately spawns WinDBG. Filter as needed.

Associated Analytic Story

• DarkGate Malware

Risk Based Analytics (RBA)

References

• https://github.com/PaloAltoNetworks/Unit42-timely-threat-intel/blob/main/2023-10-25-IOCs-from-DarkGate-activity.txt

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: 4