splunk-security_content/docs/_posts/2021-05-13-slui_spawning_a_process.md

title, excerpt, categories, last_modified_at, toc, toc_label, tags

title	excerpt	categories	last_modified_at	toc	toc_label	tags
SLUI Spawning a Process	Bypass User Account Control , Abuse Elevation Control Mechanism	Endpoint	2021-05-13	true		Bypass User Account Control Abuse Elevation Control Mechanism Defense Evasion Privilege Escalation Defense Evasion Privilege Escalation Splunk Enterprise Splunk Enterprise Security Splunk Cloud Endpoint

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Description

The following analytic identifies the Microsoft Software Licensing User Interface Tool, slui.exe, spawning a child process. This behavior is associated with publicly known UAC bypass. slui.exe is commonly associated with software updates and is most often spawned by svchost.exe. The slui.exe process should not have child processes, and any processes spawning from it will be running with elevated privileges. During triage, review the child process and additional parallel processes. Identify any file modifications that may have lead to the bypass.

• Type: TTP
• Product: Splunk Enterprise, Splunk Enterprise Security, Splunk Cloud
• Datamodel: Endpoint- Datasource: Splunk Add-on for Sysmon
• Last Updated: 2021-05-13
• Author: Michael Haag, Splunk
• ID: 879c4330-b3e0-11eb-b1b1-acde48001122

Annotations

ATT&CK

ID	Technique	Tactic
T1548.002	Bypass User Account Control	Defense Evasion, Privilege Escalation

| T1548 | Abuse Elevation Control Mechanism | Defense Evasion, Privilege Escalation |

Kill Chain Phase

• Exploitation

NIST

CIS20

CVE

Search

| 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 Processes.process_name Processes.process Processes.process_id Processes.parent_process_id 
| `drop_dm_object_name(Processes)` 
| `security_content_ctime(firstTime)` 
| `security_content_ctime(lastTime)` 
| `slui_spawning_a_process_filter`

Macros

The SPL above uses the following Macros:

• security_content_ctime
• security_content_summariesonly

ℹ️ slui_spawning_a_process_filter is a empty macro by default. It allows the user to filter out any results (false positives) without editing the SPL.

Required field

• _time
• Processes.dest
• Processes.user
• Processes.parent_process
• Processes.process_name
• Processes.process
• Processes.process_id
• Processes.parent_process_id

How To Implement

To successfully implement this search you need to be ingesting information on process that include the name of the process responsible for the changes from your endpoints into the Endpoint datamodel in the Processes node.

Known False Positives

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

Associated Analytic story

• DarkSide Ransomware
• Windows Defense Evasion Tactics

RBA

Risk Score	Impact	Confidence	Message
63.0	70	90	A slui process parent_process_name spawning child process process_name in host dest

ℹ️ The Risk Score is calculated by the following formula: Risk Score = (Impact * Confidence/100). Initial Confidence and Impact is set by the analytic author.

Reference

• 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

Test Dataset

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

• https://media.githubusercontent.com/media/splunk/attack_data/master/datasets/attack_techniques/T1548.002/slui/windows-sysmon.log

source | version: 1