Detection rules › Splunk
UAC Bypass With Colorui COM Object
The following analytic detects a potential UAC bypass using the colorui.dll COM Object. It leverages Sysmon EventCode 7 to identify instances where colorui.dll is loaded by a process other than colorcpl.exe, excluding common system directories. This activity is significant because UAC bypass techniques are often used by malware, such as LockBit ransomware, to gain elevated privileges without user consent. If confirmed malicious, this could allow an attacker to execute code with higher privileges, leading to further system compromise and persistence within the environment.
MITRE ATT&CK coverage
| Tactic | Techniques |
|---|---|
| Stealth | T1218.003 System Binary Proxy Execution: CMSTP |
Event coverage
| Provider | Event | Title |
|---|---|---|
| Sysmon | Event ID 7 | Image loaded |
Rule body splunk
name: UAC Bypass With Colorui COM Object
id: 2bcccd20-fc2b-11eb-8d22-acde48001122
version: 11
creation_date: '2021-08-13'
modification_date: '2026-05-13'
author: Teoderick Contreras, Splunk
status: production
type: TTP
description: The following analytic detects a potential UAC bypass using the colorui.dll COM Object. It leverages Sysmon EventCode 7 to identify instances where colorui.dll is loaded by a process other than colorcpl.exe, excluding common system directories. This activity is significant because UAC bypass techniques are often used by malware, such as LockBit ransomware, to gain elevated privileges without user consent. If confirmed malicious, this could allow an attacker to execute code with higher privileges, leading to further system compromise and persistence within the environment.
data_source:
- Sysmon EventID 7
search: '`sysmon` EventCode=7 ImageLoaded="*\\colorui.dll" process_name != "colorcpl.exe" NOT(Image IN("*\\windows\\*", "*\\program files*")) | fillnull | stats count min(_time) as firstTime max(_time) as lastTime by Image ImageLoaded dest loaded_file loaded_file_path original_file_name process_exec process_guid process_hash process_id process_name process_path service_dll_signature_exists service_dll_signature_verified signature signature_id user_id vendor_product | `security_content_ctime(firstTime)` | `security_content_ctime(lastTime)` | `uac_bypass_with_colorui_com_object_filter`'
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.
references:
- https://news.sophos.com/en-us/2020/04/24/lockbit-ransomware-borrows-tricks-to-keep-up-with-revil-and-maze/
drilldown_searches:
- name: View the detection results for - "$dest$"
search: '%original_detection_search% | search dest = "$dest$"'
earliest_offset: $info_min_time$
latest_offset: $info_max_time$
- name: View risk events for the last 7 days for - "$dest$"
search: '| from datamodel Risk.All_Risk | search normalized_risk_object IN ("$dest$") | stats count min(_time) as firstTime max(_time) as lastTime values(search_name) as "Search Name" values(risk_message) as "Risk Message" values(analyticstories) as "Analytic Stories" values(annotations._all) as "Annotations" values(annotations.mitre_attack.mitre_tactic) as "ATT&CK Tactics" by normalized_risk_object | `security_content_ctime(firstTime)` | `security_content_ctime(lastTime)`'
earliest_offset: 7d
latest_offset: "0"
finding:
title: The following module $ImageLoaded$ was loaded by a non-standard application on endpoint $dest$.
entity:
field: dest
type: system
score: 50
analytic_story:
- Ransomware
- LockBit Ransomware
asset_type: Endpoint
mitre_attack_id:
- T1218.003
product:
- Splunk Enterprise
- Splunk Enterprise Security
- Splunk Cloud
category: endpoint
security_domain: endpoint
tests:
- name: True Positive Test
attack_data:
- data: https://media.githubusercontent.com/media/splunk/attack_data/master/datasets/attack_techniques/T1546.015/uac_colorui/windows-sysmon.log
source: XmlWinEventLog:Microsoft-Windows-Sysmon/Operational
sourcetype: XmlWinEventLog
test_type: unit
Stages and Predicates
Stage 1: search
`sysmon` EventCode=7 ImageLoaded="*\\colorui.dll" process_name != "colorcpl.exe" NOT(Image IN("*\\windows\\*", "*\\program files*"))
Stage 2: fillnull
| fillnull
Stage 3: stats
| stats count min(_time) as firstTime max(_time) as lastTime by Image ImageLoaded dest loaded_file loaded_file_path original_file_name process_exec process_guid process_hash process_id process_name process_path service_dll_signature_exists service_dll_signature_verified signature signature_id user_id vendor_product
Stage 4: search
| `security_content_ctime(firstTime)`
Stage 5: search
| `security_content_ctime(lastTime)`
Stage 6: search
| `uac_bypass_with_colorui_com_object_filter`
Exclusions
Top-level NOT(...) conjuncts: predicates this rule actively suppresses.
| Field | Kind | Excluded values |
|---|---|---|
Image | in | "*\\program files*", "*\\windows\\*" |
Indicators
Each row is a field, operator, and value that the rule matches. The corpus column counts how many other rules in the catalog look for the same combination: high numbers point to widely-used, community-vetted indicators. Blank or 1 shows that the indicator is specific to this rule.
| Field | Kind | Values |
|---|---|---|
EventCode | eq |
|
ImageLoaded | eq |
|
process_name | ne |
|