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Description

This search is to detect a possible uac bypass using the colorui.dll COM Object. this technique was seen in so many malware and ransomware like lockbit where it make use of the colorui.dll COM CLSID to bypass UAC.

  • Type: TTP
  • Product: Splunk Enterprise, Splunk Enterprise Security, Splunk Cloud
  • Datamodel: Endpoint
  • Last Updated: 2021-08-13
  • Author: Teoderick Contreras, Splunk
  • ID: 2bcccd20-fc2b-11eb-8d22-acde48001122

Annotations

ATT&CK
ID Technique Tactic
T1218 Signed Binary Proxy Execution Defense Evasion
T1218.003 CMSTP Defense Evasion
Kill Chain Phase
  • Exploitation
NIST
CIS20
CVE 
1
2
3
4
5

`sysmon` EventCode=7 ImageLoaded="*\\colorui.dll" process_name != "colorcpl.exe" NOT(Image IN("*\\windows\\*", "*\\program files*")) 
| stats count min(_time) as firstTime max(_time) as lastTime by Image ImageLoaded process_name Computer EventCode Signed ProcessId 
| `security_content_ctime(firstTime)` 
| `security_content_ctime(lastTime)` 
| `uac_bypass_with_colorui_com_object_filter`

Macros

The SPL above uses the following Macros:

Note that uac_bypass_with_colorui_com_object_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
  • Image
  • ImageLoaded
  • process_name
  • Computer
  • EventCode
  • Signed
  • ProcessId

How To Implement

To successfully implement this search, you need to be ingesting logs with the process name, parent process, and command-line executions from your endpoints. If you are using Sysmon, you must have at least version 6.0.4 of the Sysmon TA.

Known False Positives

not so common. but 3rd part app may load this dll.

Associated Analytic story

RBA

Risk Score Impact Confidence Message
48.0 60 80 The following module $ImageLoaded$ was loaded by a non-standard application on endpoint $Computer$ by user $user$.

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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