Detectionhighstable

CMSTP UAC Bypass via COM Object Access

Detects UAC Bypass Attempt Using Microsoft Connection Manager Profile Installer Autoelevate-capable COM Objects (e.g. UACMe ID of 41, 43, 58 or 65)

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Launch
Nik Seetharaman, Christian Burkard (Nextron Systems)Created Wed Jul 31Updated Sun Dec 014b60e6f2-bf39-47b4-b4ea-398e33cfe253windows
Log Source
WindowsProcess Creation
ProductWindows← raw: windows
CategoryProcess Creation← raw: process_creation

Events generated when a new process is spawned on the system. Covers command-line arguments, parent/child relationships, and process metadata.

Detection Logic
Detection Logic1 selector
detection:
    selection:
        ParentImage|endswith: '\DllHost.exe'
        ParentCommandLine|contains:
            - ' /Processid:{3E5FC7F9-9A51-4367-9063-A120244FBEC7}' # cmstplua.dll
            - ' /Processid:{3E000D72-A845-4CD9-BD83-80C07C3B881F}' # CMLUAUTIL
            - ' /Processid:{BD54C901-076B-434E-B6C7-17C531F4AB41}' # EditionUpgradeManagerObj.dll
            - ' /Processid:{D2E7041B-2927-42FB-8E9F-7CE93B6DC937}' # colorui.dll
            - ' /Processid:{E9495B87-D950-4AB5-87A5-FF6D70BF3E90}' # wscui.cpl
        IntegrityLevel:
            - 'High'
            - 'System'
            - 'S-1-16-16384' # System
            - 'S-1-16-12288' # High
    condition: selection
False Positives

Legitimate CMSTP use (unlikely in modern enterprise environments)

Rule Metadata
Rule ID
4b60e6f2-bf39-47b4-b4ea-398e33cfe253
Status
stable
Level
high
Type
Detection
Created
Wed Jul 31
Modified
Sun Dec 01
Path
rules/windows/process_creation/proc_creation_win_uac_bypass_cmstp_com_object_access.yml
Raw Tags
attack.executionattack.defense-evasionattack.privilege-escalationattack.t1548.002attack.t1218.003attack.g0069car.2019-04-001
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