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Description

The following analytic identifies the Microsoft Software Licensing User Interface Tool, slui.exe, elevating access using the -verb runas function. This particular bypass utilizes a registry key/value. Identified by two sources, the registry keys are HKCU\Software\Classes\exefile\shell and HKCU\Software\Classes\launcher.Systemsettings\Shell\open\command. To simulate this behavior, multiple POC are available. The analytic identifies the use of runas by slui.exe.

  • 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: 8d124810-b3e4-11eb-96c7-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
1
2
3
4
5
6
| tstats `security_content_summariesonly` count min(_time) as firstTime max(_time) as lastTime from datamodel=Endpoint.Processes where Processes.process_name=slui.exe (Processes.process=*-verb* Processes.process=*runas*) 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_runas_elevated_filter`

Macros

The SPL above uses the following Macros:

Note that slui_runas_elevated_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

Limited false positives should be present as this is not commonly used by legitimate applications.

Associated Analytic story

RBA

Risk Score Impact Confidence Message
63.0 70 90 A slui process $process_name$ with elevated commandline $process$ in host $dest$

Reference

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

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