AppX Located in Uncommon Directory Added to Deployment Pipeline

calendar Apr 28, 2026 · attack.stealth  ·
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Detects an appx package that was added to the pipeline of the "to be processed" packages that is located in uncommon locations.

Sigma rule (View on GitHub)

 1title: AppX Located in Uncommon Directory Added to Deployment Pipeline
 2id: c977cb50-3dff-4a9f-b873-9290f56132f1
 3status: test
 4description: |
 5        Detects an appx package that was added to the pipeline of the "to be processed" packages that is located in uncommon locations.
 6references:
 7    - Internal Research
 8    - https://www.sentinelone.com/labs/inside-malicious-windows-apps-for-malware-deployment/
 9    - https://learn.microsoft.com/en-us/windows/win32/appxpkg/troubleshooting
10    - https://news.sophos.com/en-us/2021/11/11/bazarloader-call-me-back-attack-abuses-windows-10-apps-mechanism/
11author: Nasreddine Bencherchali (Nextron Systems)
12date: 2023-01-11
13modified: 2025-12-03
14tags:
15    - attack.stealth
16logsource:
17    product: windows
18    service: appxdeployment-server
19detection:
20    selection:
21        EventID: 854
22    filter_main_generic:
23        Path|contains:
24            # Paths can be written using forward slash if the "file://" protocol is used
25            - ':/Program%20Files' # Also covers 'file:///C:/Program%20Files%20(x86)/'
26            - ':/Windows/System32/'
27            - ':\Program Files (x86)\'
28            - ':\Program Files\'
29            - ':\Windows\ImmersiveControlPanel\'
30            - ':\Windows\PrintDialog\'
31            - ':\Windows\SystemApps\'
32            - 'AppData/Local/Temp/WinGet/Microsoft.Winget.Source'
33            - 'x-windowsupdate://'
34    filter_main_specific:
35        Path|contains:
36            - 'https://installer.teams.static.microsoft/'
37            - 'https://res.cdn.office.net' # Example https://res.cdn.office.net/nativehost/5mttl/installer/v2/1.2025.617.100/Microsoft.OutlookForWindows_x64.msix
38            - 'https://statics.teams.cdn.live.net/'
39            - 'https://statics.teams.cdn.office.net/'
40            - 'microsoft.com' # Example: https://go.microsoft.com/fwlink/?linkid=2160968
41    filter_optional_onedrive:
42        Path|contains: 'AppData\Local\Microsoft\OneDrive\'
43    filter_optional_winget:
44        Path|contains:
45            - 'AppData/Local/Temp/WinGet/Microsoft.Winget.Source'
46            - 'AppData\Local\Temp\WinGet\Microsoft.Winget.Source'
47    filter_optional_x_windowsupdate:
48        Path|contains: 'x-windowsupdate://'
49    condition: selection and not 1 of filter_main_* and not 1 of filter_optional_*
50falsepositives:
51    - Unknown
52level: medium

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