AppX Package Installation Attempts Via AppInstaller.EXE

Status: test
Severity: medium
Log source: category dns_query, product windows
Author: frack113
Source: github.com/SigmaHQ/sigma

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

MITRE ATT&CK coverage

Tactic	Techniques
Command & Control	`T1105` Ingress Tool Transfer

Telemetry coverage

Provider	Record / event type
Sysmon	Event ID 22: DNSEvent (DNS query)

Rule body

title: AppX Package Installation Attempts Via AppInstaller.EXE
id: 7cff77e1-9663-46a3-8260-17f2e1aa9d0a
related:
    - id: 180c7c5c-d64b-4a63-86e9-68910451bc8b
      type: derived
status: test
description: |
    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
references:
    - https://twitter.com/notwhickey/status/1333900137232523264
    - https://lolbas-project.github.io/lolbas/Binaries/AppInstaller/
author: frack113
date: 2021-11-24
modified: 2023-11-09
tags:
    - attack.command-and-control
    - attack.t1105
logsource:
    product: windows
    category: dns_query
detection:
    selection:
        Image|startswith: 'C:\Program Files\WindowsApps\Microsoft.DesktopAppInstaller_'
        Image|endswith: '\AppInstaller.exe'
    condition: selection
falsepositives:
    - Unknown
level: medium

Stages and Predicates

Stage 0: `condition`

selection

Stage 1: `selection`

selection:
    Image|startswith: 'C:\Program Files\WindowsApps\Microsoft.DesktopAppInstaller_'
    Image|endswith: '\AppInstaller.exe'

Indicators

These rows show field, operator, and value matches.

Field	Kind	Values	Search
`Image`	ends_with	`\AppInstaller.exe`	`field:"Image" kind:ends_with value:"\AppInstaller.exe"`
`Image`	starts_with	`C:\Program Files\WindowsApps\Microsoft.DesktopAppInstaller_`	`field:"Image" kind:starts_with value:"C:\Program Files\WindowsApps\Microsoft.DesktopAppInstaller_"`