CMSTP App Paths Registry Key Modification

Detects modifications to the CMSTP App Paths registry key. This may indicate abuse of Microsoft Connection Manager Profile Installer (CMSTP) for arbitrary code execution or UAC bypass.

title: CMSTP App Paths Registry Key Modification
id: b6d235fc-1d38-4b12-adbe-325f06728f37
status: stable
description: |
    Detects modifications to the CMSTP App Paths registry key. This may indicate abuse of
    Microsoft Connection Manager Profile Installer (CMSTP) for arbitrary code execution or UAC bypass.
references:
    - https://lolbas-project.github.io/lolbas/Binaries/Cmstp/
    - https://web.archive.org/web/20190720093911/http://www.endurant.io/cmstp/detecting-cmstp-enabled-code-execution-and-uac-bypass-with-sysmon/
    - https://web.archive.org/web/20190722224110/https://oddvar.moe/2017/08/15/research-on-cmstp-exe/
author: Nik Seetharaman
date: 2018-07-16
modified: 2026-08-27
tags:
    - attack.execution
    - attack.stealth
    - attack.t1218.003
    - attack.g0069
    - car.2019-04-001
logsource:
    category: registry_event
    product: windows
detection:
    selection:
        TargetObject|contains: 'SOFTWARE\Microsoft\Windows\CurrentVersion\App Paths\cmmgr32.exe\'
    filter_main_cmcfg32:
        TargetObject|endswith: 'SOFTWARE\Microsoft\Windows\CurrentVersion\App Paths\cmmgr32.exe\CmstpExtensionDll'
        Details:
            - 'C:\Windows\System32\cmcfg32.dll'
            - 'C:\Windows\SysWOW64\cmcfg32.dll'
    filter_main_empty:
        Details: '(Empty)'
    condition: selection and not 1 of filter_main_*
falsepositives:
    - Legitimate CMSTP use (unlikely in modern enterprise environments)
level: high

• T1218.003CMSTP

• G0069MuddyWater

• https://lolbas-project.github.io/lolbas/Binaries/Cmstp/↗
• https://web.archive.org/web/20190720093911/http://www.endurant.io/cmstp/detecting-cmstp-enabled-code-execution-and-uac-bypass-with-sysmon/↗
• https://web.archive.org/web/20190722224110/https://oddvar.moe/2017/08/15/research-on-cmstp-exe/↗