Detectionmediumtest

Office Autorun Keys Modification

Detects modification of autostart extensibility point (ASEP) in registry. Adversaries may modify these keys to execute malicious code when Office files are opened. There are various legitimate add-ins that also use these keys and this filter list might not be exhaustive. Thus, it is recommended to review and tune filters for your environment to reduce false positives before deploying to production.

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Launch

Victor Sergeev, Daniil Yugoslavskiy, Gleb Sukhodolskiy, Timur Zinniatullin, oscd.community, Tim Shelton, François HubautCreated Fri Oct 25Updated Fri Jan 09baecf8fb-edbf-429f-9ade-31fc3f22b970windows

Log Source

WindowsRegistry Set

ProductWindows← raw: windows

CategoryRegistry Set← raw: registry_set

Detection Logic

detection:
    selection_office_root:
        TargetObject|contains:
            - '\Software\Wow6432Node\Microsoft\Office'
            - '\Software\Microsoft\Office'
    selection_office_details:
        TargetObject|contains:
            - '\Word\Addins'
            - '\PowerPoint\Addins'
            - '\Outlook\Addins'
            - '\Onenote\Addins'
            - '\Excel\Addins'
            - '\Access\Addins'
            - 'test\Special\Perf'
    filter_main_empty:
        Details: '(Empty)'
    filter_main_null:
        Details: null
    filter_main_known_addins:
        Image|startswith:
            - 'C:\Program Files\Microsoft Office\'
            - 'C:\Program Files (x86)\Microsoft Office\'
            - 'C:\PROGRA~2\MICROS~2\Office'
            - 'C:\Windows\System32\msiexec.exe'
            - 'C:\Windows\SysWOW64\msiexec.exe'
            - 'C:\Windows\System32\regsvr32.exe'
            - 'C:\Windows\SysWOW64\regsvr32.exe '
        TargetObject|contains:
            # Remove any unused addins in your environment from the filter
            # Known addins for excel
            - '\Excel\Addins\AdHocReportingExcelClientLib.AdHocReportingExcelClientAddIn.1\'
            - '\Excel\Addins\ExcelPlugInShell.PowerMapConnect\'
            - '\Excel\Addins\NativeShim\'
            - '\Excel\Addins\NativeShim.InquireConnector.1\'
            - '\Excel\Addins\PowerPivotExcelClientAddIn.NativeEntry.1\'
            # Known addins for outlook
            - '\Outlook\AddIns\AccessAddin.DC\'
            - '\Outlook\AddIns\ColleagueImport.ColleagueImportAddin\'
            - '\Outlook\AddIns\EvernoteCC.EvernoteContactConnector\'
            - '\Outlook\AddIns\EvernoteOLRD.Connect\'
            # - '\Outlook\Addins\GrammarlyAddIn.Connect' # Uncomment if you use Grammarly
            - '\Outlook\Addins\\OneNote.OutlookAddin'
            - '\Outlook\Addins\DriveFSExtensionLib.Connect\' # An Outlook Add-in to talk with Google Drive
            - '\Outlook\Addins\GoogleAppsSync.Connect\' # Google Apps Sync for Microsoft Outlook
            - '\Outlook\Addins\Microsoft.VbaAddinForOutlook.1\'
            - '\Outlook\Addins\OcOffice.OcForms\'
            - '\Outlook\Addins\OscAddin.Connect\'
            - '\Outlook\Addins\OutlookChangeNotifier.Connect\'
            - '\Outlook\Addins\UCAddin.LyncAddin.1'
            - '\Outlook\Addins\UCAddin.UCAddin.1'
            - '\Outlook\Addins\UmOutlookAddin.FormRegionAddin\'
            - 'AddinTakeNotesService\FriendlyName'
    filter_main_officeclicktorun:
        Image|startswith:
            - 'C:\Program Files\Common Files\Microsoft Shared\ClickToRun\'
            - 'C:\Program Files\Common Files\Microsoft Shared\ClickToRun\Updates\'
        Image|endswith: '\OfficeClickToRun.exe'
    filter_main_vsto:
        Image|startswith:
            - 'C:\Program Files\Common Files\Microsoft Shared\VSTO\'
            - 'C:\Program Files (x86)\Microsoft Shared\VSTO\'
        Image|endswith: '\VSTOInstaller.exe'
    filter_optional_avg:
        Image:
            - 'C:\Program Files\AVG\Antivirus\RegSvr.exe'
            - 'C:\Program Files\AVG\Antivirus\x86\RegSvr.exe'
        TargetObject|contains: '\Microsoft\Office\Outlook\Addins\Antivirus.AsOutExt\'
    filter_optional_avast:
        Image:
            - 'C:\Program Files\Avast Software\Avast\RegSvr.exe'
            - 'C:\Program Files\Avast Software\Avast\x86\RegSvr.exe'
        TargetObject|contains: '\Microsoft\Office\Outlook\Addins\Avast.AsOutExt\'
    # These filters are not exhaustive, filter can be expanded based on environment
    condition: all of selection_office_* and not 1 of filter_main_* and not 1 of filter_optional_*