Sigma rule: Unsigned AppX Installation Attempt Using Add-AppxPackage - PsScript

A detection rule from the SigmaHQ repository, shown as its author published it. Dataset version ref-f1268a8abcb7, updated 2023-01-31T00:00:00.000Z.

Rule

Title
Unsigned AppX Installation Attempt Using Add-AppxPackage - PsScript
Status
test
Level
medium
Author
Nasreddine Bencherchali (Nextron Systems)
Date
2023-01-31
File
rules/windows/powershell/powershell_script/posh_ps_install_unsigned_appx_packages.yml
Commit
ccbb0369507f796db0b0ae6854c8a2be471b9d84

Detects usage of the "Add-AppxPackage" or it's alias "Add-AppPackage" to install unsigned AppX packages

Log source

product
windows
category
ps_script
definition
Script Block Logging must be enable

Detection

selection_cmdlet:
    ScriptBlockText|contains:
        - 'Add-AppPackage '
        - 'Add-AppxPackage '
selection_flag:
    ScriptBlockText|contains: ' -AllowUnsigned'
condition: all of selection_*

False positives (as the rule lists them)

  • Installation of unsigned packages for testing purposes

Tags

  • attack.persistence
  • attack.stealth

Related rules

References

Read on 2026-11-03T00:58:21.399Z under licence sigma-drl-1.1@d5f4c36a from https://github.com/SigmaHQ/sigma/blob/ccbb0369507f796db0b0ae6854c8a2be471b9d84/rules/windows/powershell/powershell_script/posh_ps_install_unsigned_appx_packages.yml

Sources and licences

  • SigmaHQ

    "Unsigned AppX Installation Attempt Using Add-AppxPackage - PsScript" by Nasreddine Bencherchali (Nextron Systems) (SigmaHQ). Rule: https://github.com/SigmaHQ/sigma/blob/ccbb0369507f796db0b0ae6854c8a2be471b9d84/rules/windows/powershell/powershell_script/posh_ps_install_unsigned_appx_packages.yml.
    Licensed under the Detection Rule License (DRL) 1.1: https://github.com/SigmaHQ/Detection-Rule-License

    Detection Rule License (DRL) 1.1

Cite this page

Dragons Eye Ransomware Tracker, "Sigma rule: Unsigned AppX Installation Attempt Using Add-AppxPackage - PsScript",
entity page, dataset version ref-f1268a8abcb7, updated 2023-01-31T00:00:00.000Z,
https://ransomware-tracker.com/detections/sigma/975b2262-9a49-439d-92a6-0709cccdf0b2 (accessed 2026-11-03).
Underlying source: SigmaHQ rule 975b2262-9a49-439d-92a6-0709cccdf0b2, commit ccbb0369507f796db0b0ae6854c8a2be471b9d84.

Pages change. The dataset version identifies the data, but no archive of old versions is kept, so this citation cannot be replayed later.