title: COM Object Hijacking Via Modification Of Default System CLSID Default Value
id: 790317c0-0a36-4a6a-a105-6e576bf99a14
related:
    - id: 3d968d17-ffa4-4bc0-bfdc-f139de76ce77
      type: obsolete
    - id: a0ff33d8-79e4-4cef-b4f3-9dc4133ccd12
      type: obsolete
status: experimental
description: Detects potential COM object hijacking via modification of default system CLSID.
references:
    - https://www.microsoft.com/security/blog/2022/07/27/untangling-knotweed-european-private-sector-offensive-actor-using-0-day-exploits/ (idea)
    - https://unit42.paloaltonetworks.com/snipbot-romcom-malware-variant/
    - https://blog.talosintelligence.com/uat-5647-romcom/
    - https://global.ptsecurity.com/analytics/pt-esc-threat-intelligence/darkhotel-a-cluster-of-groups-united-by-common-techniques
    - https://threatbook.io/blog/Analysis-of-APT-C-60-Attack-on-South-Korea
    - https://catalyst.prodaft.com/public/report/inside-the-latest-espionage-campaign-of-nebulous-mantis
    - https://github.com/rtecCyberSec/BitlockMove
    - https://cert.gov.ua/article/6284080
    - https://securelist.com/forumtroll-apt-hacking-team-dante-spyware/117851/
author: Nasreddine Bencherchali (Nextron Systems)
date: 2024-07-16
modified: 2025-11-10
tags:
    - attack.privilege-escalation
    - attack.persistence
    - attack.t1546.015
logsource:
    category: registry_set
    product: windows
detection:
    selection_target_root:
        TargetObject|contains: '\CLSID\'
        TargetObject|endswith:
            - '\InprocServer32\(Default)'
            - '\LocalServer32\(Default)'
    selection_target_builtin_clsid:
        TargetObject|contains:
            # Note: Add other legitimate CLSID
            - '\{1f486a52-3cb1-48fd-8f50-b8dc300d9f9d}\'
            - '\{2155fee3-2419-4373-b102-6843707eb41f}\'
            - '\{4590f811-1d3a-11d0-891f-00aa004b2e24}\'
            - '\{4de225bf-cf59-4cfc-85f7-68b90f185355}\'
            - '\{ddc05a5a-351a-4e06-8eaf-54ec1bc2dcea}\'
            - '\{F56F6FDD-AA9D-4618-A949-C1B91AF43B1A}\'
            - '\{F82B4EF1-93A9-4DDE-8015-F7950A1A6E31}\'
            - '\{7849596a-48ea-486e-8937-a2a3009f31a9}\'
            - '\{0b91a74b-ad7c-4a9d-b563-29eef9167172}\'
            - '\{603D3801-BD81-11d0-A3A5-00C04FD706EC}\'
            - '\{30D49246-D217-465F-B00B-AC9DDD652EB7}\'
            - '\{A7A63E5C-3877-4840-8727-C1EA9D7A4D50}\'
            - '\{2227A280-3AEA-1069-A2DE-08002B30309D}\'
            - '\{2DEA658F-54C1-4227-AF9B-260AB5FC3543}\'
            - '\{AA509086-5Ca9-4C25-8F95-589D3C07B48A}\'
    selection_susp_location_1:
        Details|contains:
            # Note: Add more suspicious paths and locations
            - ':\Perflogs\'
            - '\AppData\Local\'
            - '\Desktop\'
            - '\Downloads\'
            - '\Microsoft\Windows\Start Menu\Programs\Startup\'
            - '\System32\spool\drivers\color\' # as seen in the knotweed blog
            - '\Temporary Internet'
            - '\Users\Public\'
            - '\Windows\Temp\'
            - '%appdata%'
            - '%temp%'
            - '%tmp%'
    selection_susp_location_2:
        - Details|contains|all:
              - ':\Users\'
              - '\Favorites\'
        - Details|contains|all:
              - ':\Users\'
              - '\Favourites\'
        - Details|contains|all:
              - ':\Users\'
              - '\Contacts\'
        - Details|contains|all:
              - ':\Users\'
              - '\Pictures\'
    condition: all of selection_target_* and 1 of selection_susp_location_*
falsepositives:
    - Unlikely
level: high

title: Potential PSFactoryBuffer COM Hijacking
id: 243380fa-11eb-4141-af92-e14925e77c1b
status: test
description: Detects changes to the PSFactory COM InProcServer32 registry. This technique was used by RomCom to create persistence storing a malicious DLL.
references:
    - https://blogs.blackberry.com/en/2023/06/romcom-resurfaces-targeting-ukraine
    - https://strontic.github.io/xcyclopedia/library/clsid_C90250F3-4D7D-4991-9B69-A5C5BC1C2AE6.html
    - https://www.virustotal.com/gui/file/6d3ab9e729bb03ae8ae3fcd824474c5052a165de6cb4c27334969a542c7b261d/detection
    - https://www.trendmicro.com/en_us/research/23/e/void-rabisu-s-use-of-romcom-backdoor-shows-a-growing-shift-in-th.html
author: BlackBerry Threat Research and Intelligence Team - @Joseliyo_Jstnk
date: 2023-06-07
modified: 2023-08-17
tags:
    - attack.privilege-escalation
    - attack.persistence
    - attack.t1546.015
logsource:
    category: registry_set
    product: windows
detection:
    selection:
        TargetObject|endswith: '\CLSID\{c90250f3-4d7d-4991-9b69-a5c5bc1c2ae6}\InProcServer32\(Default)'
    filter_main:
        Details:
            - '%windir%\System32\ActXPrxy.dll'
            - 'C:\Windows\System32\ActXPrxy.dll'
    condition: selection and not filter_main
falsepositives:
    - Unknown
level: high

title: Rundll32 Registered COM Objects
id: f1edd233-30b5-4823-9e6a-c4171b24d316
status: test
description: load malicious registered COM objects
references:
    - https://nasbench.medium.com/a-deep-dive-into-rundll32-exe-642344b41e90
    - https://github.com/redcanaryco/atomic-red-team/blob/f339e7da7d05f6057fdfcdd3742bfcf365fee2a9/atomics/T1546.015/T1546.015.md
author: frack113
date: 2022-02-13
modified: 2023-02-09
tags:
    - attack.privilege-escalation
    - attack.persistence
    - attack.t1546.015
logsource:
    category: process_creation
    product: windows
detection:
    selection_img:
        - Image|endswith: '\rundll32.exe'
        - OriginalFileName: 'RUNDLL32.EXE'
    selection_cli:
        CommandLine|contains:
            - '-sta '
            - '-localserver '
        CommandLine|contains|all:
            - '{'
            - '}'
    condition: all of selection_*
falsepositives:
    - Legitimate use
level: high

title: COM Hijacking via TreatAs
id: dc5c24af-6995-49b2-86eb-a9ff62199e82
status: test
description: Detect modification of TreatAs key to enable "rundll32.exe -sta" command
references:
    - https://github.com/redcanaryco/atomic-red-team/blob/40b77d63808dd4f4eafb83949805636735a1fd15/atomics/T1546.015/T1546.015.md
    - https://www.youtube.com/watch?v=3gz1QmiMhss&t=1251s
author: frack113
date: 2022-08-28
modified: 2025-07-11
tags:
    - attack.privilege-escalation
    - attack.persistence
    - attack.t1546.015
logsource:
    category: registry_set
    product: windows
detection:
    selection:
        TargetObject|endswith: 'TreatAs\(Default)'
    filter_office:
        Image|startswith: 'C:\Program Files\Common Files\Microsoft Shared\ClickToRun\'
        Image|endswith: '\OfficeClickToRun.exe'
    filter_office2:
        Image:
            - 'C:\Program Files\Microsoft Office\root\integration\integrator.exe'
            - 'C:\Program Files (x86)\Microsoft Office\root\integration\integrator.exe'
    filter_svchost:
        # Example of target object by svchost
        # TargetObject: HKLM\SOFTWARE\Microsoft\MsixRegistryCompatibility\Package\Microsoft.Paint_11.2208.6.0_x64__8wekyb3d8bbwe\User\SOFTWARE\Classes\CLSID\{0003000A-0000-0000-C000-000000000046}\TreatAs\(Default)
        # TargetObject: HKU\S-1-5-21-1000000000-000000000-000000000-0000_Classes\CLSID\{0003000A-0000-0000-C000-000000000046}\TreatAs\(Default)
        Image: 'C:\Windows\system32\svchost.exe'
    filter_misexec:
        # This FP has been seen during installation/updates
        Image:
            - 'C:\Windows\system32\msiexec.exe'
            - 'C:\Windows\SysWOW64\msiexec.exe'
    condition: selection and not 1 of filter_*
falsepositives:
    - Legitimate use
level: medium

title: Potential COM Object Hijacking Via TreatAs Subkey - Registry
id: 9b0f8a61-91b2-464f-aceb-0527e0a45020
status: test
description: Detects COM object hijacking via TreatAs subkey
references:
    - https://bohops.com/2018/08/18/abusing-the-com-registry-structure-part-2-loading-techniques-for-evasion-and-persistence/
author: Kutepov Anton, oscd.community
date: 2019-10-23
modified: 2025-10-26
tags:
    - attack.privilege-escalation
    - attack.persistence
    - attack.t1546.015
logsource:
    category: registry_set
    product: windows
detection:
    selection:
        TargetObject|contains|all:
            - 'HKU\'
            - 'Classes\CLSID\'
            - '\TreatAs'
    filter_main_svchost:
        # Example of target object by svchost
        # TargetObject: HKU\S-1-5-21-1098798288-3663759343-897484398-1001_Classes\CLSID\{0003000A-0000-0000-C000-000000000046}\TreatAs
        Image: 'C:\WINDOWS\system32\svchost.exe'
    condition: selection and not 1 of filter_main_*
falsepositives:
    - Maybe some system utilities in rare cases use linking keys for backward compatibility
level: medium
regression_tests_path: regression_data/rules/windows/registry/registry_set/registry_set_persistence_com_key_linking/info.yml
simulation:
    - type: atomic-red-team
      name: COM hijacking via TreatAs
      technique: T1546.015
      atomic_guid: 33eacead-f117-4863-8eb0-5c6304fbfaa9

title: Potential Persistence Using DebugPath
id: df4dc653-1029-47ba-8231-3c44238cc0ae
status: test
description: Detects potential persistence using Appx DebugPath
references:
    - https://oddvar.moe/2018/09/06/persistence-using-universal-windows-platform-apps-appx/
    - https://github.com/rootm0s/WinPwnage
author: frack113
date: 2022-07-27
modified: 2023-08-17
tags:
    - attack.privilege-escalation
    - attack.persistence
    - attack.t1546.015
logsource:
    category: registry_set
    product: windows
detection:
    selection_debug:
        TargetObject|contains: 'Classes\ActivatableClasses\Package\Microsoft.'
        TargetObject|endswith: '\DebugPath'
    selection_default:
        TargetObject|contains: '\Software\Microsoft\Windows\CurrentVersion\PackagedAppXDebug\Microsoft.'
        TargetObject|endswith: '\(Default)'
    condition: 1 of selection_*
falsepositives:
    - Unknown
level: medium

title: Potential Persistence Via Scrobj.dll COM Hijacking
id: fe20dda1-6f37-4379-bbe0-a98d400cae90
status: test
description: Detect use of scrobj.dll as this DLL looks for the ScriptletURL key to get the location of the script to execute
references:
    - https://github.com/redcanaryco/atomic-red-team/blob/40b77d63808dd4f4eafb83949805636735a1fd15/atomics/T1546.015/T1546.015.md
author: frack113
date: 2022-08-20
modified: 2023-08-17
tags:
    - attack.privilege-escalation
    - attack.persistence
    - attack.t1546.015
logsource:
    category: registry_set
    product: windows
detection:
    selection:
        TargetObject|endswith: 'InprocServer32\(Default)'
        Details: 'C:\WINDOWS\system32\scrobj.dll'
    condition: selection
falsepositives:
    - Legitimate use of the dll.
level: medium

title: Suspicious GetTypeFromCLSID ShellExecute
id: 8bc063d5-3a3a-4f01-a140-bc15e55e8437
status: test
description: Detects suspicious Powershell code that execute COM Objects
references:
    - https://github.com/redcanaryco/atomic-red-team/blob/f339e7da7d05f6057fdfcdd3742bfcf365fee2a9/atomics/T1546.015/T1546.015.md#atomic-test-2---powershell-execute-com-object
author: frack113
date: 2022-04-02
tags:
    - attack.privilege-escalation
    - attack.persistence
    - attack.t1546.015
logsource:
    product: windows
    category: ps_script
    definition: 'Requirements: Script Block Logging must be enabled'
detection:
    selection:
        ScriptBlockText|contains|all:
            - '::GetTypeFromCLSID('
            - '.ShellExecute('
    condition: selection
falsepositives:
    - Legitimate PowerShell scripts
level: medium