Detection: SLUI Spawning a Process

Description

The following analytic detects the Microsoft Software Licensing User Interface Tool (slui.exe) spawning a child process. This behavior is identified using Endpoint Detection and Response (EDR) telemetry, focusing on process creation events where slui.exe is the parent process. This activity is significant because slui.exe should not typically spawn child processes, and doing so may indicate a UAC bypass attempt, leading to elevated privileges. If confirmed malicious, an attacker could leverage this to execute code with elevated privileges, potentially compromising the system's security and gaining unauthorized access.

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=slui.exe by Processes.dest Processes.user Processes.parent_process_name Processes.parent_process Processes.process_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| `slui_spawning_a_process_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

Certain applications may spawn from slui.exe that are legitimate. Filtering will be needed to ensure proper monitoring.

Associated Analytic Story

• Compromised Windows Host

• DarkSide Ransomware

• Windows Defense Evasion Tactics

Risk Based Analytics (RBA)

References

• https://www.exploit-db.com/exploits/46998

• https://www.rapid7.com/db/modules/exploit/windows/local/bypassuac_sluihijack/

• https://www.mandiant.com/resources/shining-a-light-on-darkside-ransomware-operations

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