Suspicious AppX Package Deployment Failed Due to Signing Requirements (via appxdeployment-server)

title: Suspicious AppX Package Deployment Failed Due to Signing Requirements (via appxdeployment-server)
id: 3a312c95-a5f5-5af7-8d1a-41db2c9b7de3
status: stable
description: This rule detects an appx package deployment / installation with the error code "0x80073cff" which suggests that the package didn't meet the signing requirements.
references:
    - 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: Huntrule Team
date: 2026-04-15
tags:
    - attack.stealth
    - attack.defense-evasion
    - attack.t1553
logsource:
    product: windows
    service: appxdeployment-server
detection:
    selection:
        EventID: 401
        ErrorCode: '0x80073cff'
    condition: selection
falsepositives:
    - Unknown
level: medium