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Detectionmediumtest

Potential File Download Via MS-AppInstaller Protocol Handler

Detects usage 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>"

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Launch
Nasreddine Bencherchali (Nextron Systems), Swachchhanda Shrawan PoudelCreated Thu Nov 09180c7c5c-d64b-4a63-86e9-68910451bc8bwindows
Log Source
WindowsProcess Creation
ProductWindows← raw: windows
CategoryProcess Creation← raw: process_creation

Events generated when a new process is spawned on the system. Covers command-line arguments, parent/child relationships, and process metadata.

Detection Logic
Detection Logic1 selector
detection:
    selection:
        CommandLine|contains|all:
            - 'ms-appinstaller://?source='
            - 'http'
    condition: selection
False Positives
Unknown

False positive likelihood has not been assessed. Additional context may be needed during triage.

References
1
Resolving title…
lolbas-project.github.io
MITRE ATT&CK
Related Rules
DerivedDetectionmedium

AppX Package Installation Attempts Via AppInstaller.EXE

Detects DNS queries made by "AppInstaller.EXE". The AppInstaller is the default handler for the "ms-appinstaller" URI. It attempts to load/install a package from the referenced URL

This rule was derived from the related rule - both detect similar activity with different scope.

Rule Metadata
Rule ID
180c7c5c-d64b-4a63-86e9-68910451bc8b
Status
test
Level
medium
Type
Detection
Created
Thu Nov 09
Author
Nasreddine Bencherchali (Nextron Systems), Swachchhanda Shrawan Poudel
Path
rules/windows/process_creation/proc_creation_win_susp_ms_appinstaller_download.yml
Raw Tags
attack.defense-evasionattack.executionattack.t1218
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