Possible File Download Through MS-AppInstaller Protocol Handler (via process_creation)

title: Possible File Download Through MS-AppInstaller Protocol Handler (via process_creation)
id: 0c159b28-51b3-5e0d-84ac-0b2db99e7d5a
status: stable
description: This rule detects use of the "ms-appinstaller" protocol handler via command line to potentially download arbitrary files via AppInstaller.EXE The downloaded files are temporarly stored in ":\Users\%username%\AppData\Local\Packages\Microsoft.DesktopAppInstaller_8wekyb3d8bbwe\AC\INetCache\<RANDOM-8-CHAR-DIRECTORY>"
references:
    - https://attack.mitre.org/techniques/T1218/
    - https://lolbas-project.github.io/lolbas/Binaries/AppInstaller/
author: Huntrule Team
date: 2026-01-29
tags:
    - attack.execution
    - attack.stealth
    - attack.t1218
logsource:
    category: process_creation
    product: windows
detection:
    selection:
        CommandLine|contains|all:
            - 'ms-appinstaller://?source='
            - 'http'
    condition: selection
falsepositives:
    - Unknown
level: medium