Convert indexed Sigma rules into analyst-ready detections.

title: AppX Located in Uncommon Directory Added to Deployment Pipeline
id: c977cb50-3dff-4a9f-b873-9290f56132f1
status: test
description: |
    Detects an appx package that was added to the pipeline of the "to be processed" packages that is located in uncommon locations.
references:
    - Internal Research
    - https://www.sentinelone.com/labs/inside-malicious-windows-apps-for-malware-deployment/
    - https://learn.microsoft.com/en-us/windows/win32/appxpkg/troubleshooting
    - https://news.sophos.com/en-us/2021/11/11/bazarloader-call-me-back-attack-abuses-windows-10-apps-mechanism/
author: Nasreddine Bencherchali (Nextron Systems)
date: 2023-01-11
modified: 2025-12-03
tags:
    - attack.defense-evasion
logsource:
    product: windows
    service: appxdeployment-server
detection:
    selection:
        EventID: 854
    filter_main_generic:
        Path|contains:
            # Paths can be written using forward slash if the "file://" protocol is used
            - ':/Program%20Files' # Also covers 'file:///C:/Program%20Files%20(x86)/'
            - ':/Windows/System32/'
            - ':\Program Files (x86)\'
            - ':\Program Files\'
            - ':\Windows\ImmersiveControlPanel\'
            - ':\Windows\PrintDialog\'
            - ':\Windows\SystemApps\'
            - 'AppData/Local/Temp/WinGet/Microsoft.Winget.Source'
            - 'x-windowsupdate://'
    filter_main_specific:
        Path|contains:
            - 'https://installer.teams.static.microsoft/'
            - 'https://res.cdn.office.net' # Example https://res.cdn.office.net/nativehost/5mttl/installer/v2/1.2025.617.100/Microsoft.OutlookForWindows_x64.msix
            - 'https://statics.teams.cdn.live.net/'
            - 'https://statics.teams.cdn.office.net/'
            - 'microsoft.com' # Example: https://go.microsoft.com/fwlink/?linkid=2160968
    filter_optional_onedrive:
        Path|contains: 'AppData\Local\Microsoft\OneDrive\'
    filter_optional_winget:
        Path|contains:
            - 'AppData/Local/Temp/WinGet/Microsoft.Winget.Source'
            - 'AppData\Local\Temp\WinGet\Microsoft.Winget.Source'
    filter_optional_x_windowsupdate:
        Path|contains: 'x-windowsupdate://'
    condition: selection and not 1 of filter_main_* and not 1 of filter_optional_*
falsepositives:
    - Unknown
level: medium