title: Bypass UAC via CMSTP
id: e66779cc-383e-4224-a3a4-267eeb585c40
status: test
description: Detect commandline usage of Microsoft Connection Manager Profile Installer (cmstp.exe) to install specially formatted local .INF files
references:
    - https://eqllib.readthedocs.io/en/latest/analytics/e584f1a1-c303-4885-8a66-21360c90995b.html
    - https://github.com/redcanaryco/atomic-red-team/blob/f339e7da7d05f6057fdfcdd3742bfcf365fee2a9/atomics/T1218.003/T1218.003.md
    - https://lolbas-project.github.io/lolbas/Binaries/Cmstp/
author: E.M. Anhaus (originally from Atomic Blue Detections, Endgame), oscd.community
date: 2019-10-24
modified: 2022-08-30
tags:
    - attack.privilege-escalation
    - attack.stealth
    - attack.t1548.002
    - attack.t1218.003
logsource:
    category: process_creation
    product: windows
detection:
    selection_img:
        - Image|endswith: '\cmstp.exe'
        - OriginalFileName: 'CMSTP.EXE'
    selection_cli:
        CommandLine|contains:
            - '/s'
            - '-s'
            - '/au'
            - '-au'
            - '/ni'
            - '-ni'
    condition: all of selection*
falsepositives:
    - Legitimate use of cmstp.exe utility by legitimate user
level: high

title: CMSTP Execution Process Access
id: 3b4b232a-af90-427c-a22f-30b0c0837b95
status: stable
description: Detects various indicators of Microsoft Connection Manager Profile Installer execution
references:
    - https://web.archive.org/web/20190720093911/http://www.endurant.io/cmstp/detecting-cmstp-enabled-code-execution-and-uac-bypass-with-sysmon/
author: Nik Seetharaman
date: 2018-07-16
modified: 2021-06-27
tags:
    - attack.stealth
    - attack.t1218.003
    - attack.execution
    - attack.t1559.001
    - attack.g0069
    - attack.g0080
    - car.2019-04-001
logsource:
    product: windows
    category: process_access
detection:
    # Process Access Call Trace
    selection:
        CallTrace|contains: 'cmlua.dll'
    condition: selection
falsepositives:
    - Legitimate CMSTP use (unlikely in modern enterprise environments)
level: high

title: CMSTP Execution Process Creation
id: 7d4cdc5a-0076-40ca-aac8-f7e714570e47
status: stable
description: Detects various indicators of Microsoft Connection Manager Profile Installer execution
references:
    - https://web.archive.org/web/20190720093911/http://www.endurant.io/cmstp/detecting-cmstp-enabled-code-execution-and-uac-bypass-with-sysmon/
author: Nik Seetharaman
date: 2018-07-16
modified: 2020-12-23
tags:
    - attack.execution
    - attack.stealth
    - attack.t1218.003
    - attack.g0069
    - car.2019-04-001
logsource:
    category: process_creation
    product: windows
detection:
    # CMSTP Spawning Child Process
    selection:
        ParentImage|endswith: '\cmstp.exe'
    condition: selection
falsepositives:
    - Legitimate CMSTP use (unlikely in modern enterprise environments)
level: high

title: CMSTP Execution Registry Event
id: b6d235fc-1d38-4b12-adbe-325f06728f37
status: stable
description: Detects various indicators of Microsoft Connection Manager Profile Installer execution
references:
    - https://web.archive.org/web/20190720093911/http://www.endurant.io/cmstp/detecting-cmstp-enabled-code-execution-and-uac-bypass-with-sysmon/
author: Nik Seetharaman
date: 2018-07-16
modified: 2020-12-23
tags:
    - attack.execution
    - attack.stealth
    - attack.t1218.003
    - attack.g0069
    - car.2019-04-001
logsource:
    category: registry_event
    product: windows
detection:
    selection:
        TargetObject|contains: '\cmmgr32.exe'
    condition: selection
falsepositives:
    - Legitimate CMSTP use (unlikely in modern enterprise environments)
level: high

title: CMSTP UAC Bypass via COM Object Access
id: 4b60e6f2-bf39-47b4-b4ea-398e33cfe253
status: stable
description: Detects UAC Bypass Attempt Using Microsoft Connection Manager Profile Installer Autoelevate-capable COM Objects (e.g. UACMe ID of 41, 43, 58 or 65)
references:
    - https://web.archive.org/web/20190720093911/http://www.endurant.io/cmstp/detecting-cmstp-enabled-code-execution-and-uac-bypass-with-sysmon/
    - https://twitter.com/hFireF0X/status/897640081053364225
    - https://medium.com/falconforce/falconfriday-detecting-uac-bypasses-0xff16-86c2a9107abf
    - https://github.com/hfiref0x/UACME
author: Nik Seetharaman, Christian Burkard (Nextron Systems)
date: 2019-07-31
modified: 2024-12-01
tags:
    - attack.execution
    - attack.privilege-escalation
    - attack.stealth
    - attack.t1548.002
    - attack.t1218.003
    - attack.g0069
    - car.2019-04-001
logsource:
    category: process_creation
    product: windows
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
falsepositives:
    - Legitimate CMSTP use (unlikely in modern enterprise environments)
level: high

title: DLL Loaded From Suspicious Location Via Cmspt.EXE
id: 75e508f7-932d-4ebc-af77-269237a84ce1
status: test
description: Detects cmstp loading "dll" or "ocx" files from suspicious locations
references:
    - https://github.com/vadim-hunter/Detection-Ideas-Rules/blob/02bcbfc2bfb8b4da601bb30de0344ae453aa1afe/TTPs/Defense%20Evasion/T1218%20-%20Signed%20Binary%20Proxy%20Execution/T1218.003%20-%20CMSTP/Procedures.yaml
author: Nasreddine Bencherchali (Nextron Systems)
date: 2022-08-30
modified: 2023-02-17
tags:
    - attack.stealth
    - attack.t1218.003
logsource:
    category: image_load
    product: windows
detection:
    selection:
        Image|endswith: '\cmstp.exe'
        ImageLoaded|contains:
            # Add more suspicious paths as you see fit in your env
            - '\PerfLogs\'
            - '\ProgramData\'
            - '\Users\'
            - '\Windows\Temp\'
            - 'C:\Temp\'
        ImageLoaded|endswith:
            - '.dll'
            - '.ocx'
    condition: selection
falsepositives:
    - Unikely
level: high

title: Outbound Network Connection Initiated By Cmstp.EXE
id: efafe0bf-4238-479e-af8f-797bd3490d2d
status: test
description: |
    Detects a network connection initiated by Cmstp.EXE
    Its uncommon for "cmstp.exe" to initiate an outbound network connection. Investigate the source of such requests to determine if they are malicious.
references:
    - https://web.archive.org/web/20190720093911/http://www.endurant.io/cmstp/detecting-cmstp-enabled-code-execution-and-uac-bypass-with-sysmon/
author: Nasreddine Bencherchali (Nextron Systems)
date: 2022-08-30
modified: 2024-05-31
tags:
    - attack.stealth
    - attack.t1218.003
logsource:
    category: network_connection
    product: windows
detection:
    selection:
        Image|endswith: '\cmstp.exe'
        Initiated: 'true'
    filter_main_local_ranges:
        DestinationIp|cidr:
            - '127.0.0.0/8'
            - '10.0.0.0/8'
            - '172.16.0.0/12'
            - '192.168.0.0/16'
            - '169.254.0.0/16'
            - '::1/128'  # IPv6 loopback
            - 'fe80::/10'  # IPv6 link-local addresses
            - 'fc00::/7'  # IPv6 private addresses
    condition: selection and not 1 of filter_main_*
falsepositives:
    - Unknown
# Note: Please report any false positive seen in the wild to help tune the rule.
level: high