Windows PowerShell Web Access Installation via PowerShell Script Block

Detects PowerShell Web Access installation and web authorization configuration from Windows PowerShell script blocks.

FreeReviewedSigma · High · v2

Product: windows
Category: ps_script
Author: Michael Haag (SigmaHQ), DRL 1.1
Published: 2024-09-03
Updated: 2026-07-31

ATT&CK techniques

Execution

Recon
Resource Dev
Initial Access
Execution
- T1059.001PowerShell
Persistence
Priv Esc
Defense Evasion
Cred Access
Discovery
Lateral Movement
Collection
C2
Exfiltration
Impact

What it detects

This rule identifies PowerShell activity that installs PowerShell Web Access and configures a web application and authorization rules. An attacker could use this to establish remote web-based access paths that may support persistence or follow-on abuse. The detection relies on ScriptBlockText content from PowerShell script block logging, matching installation, application setup, and authorization rule commands.

Reporting behind it

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Windows PowerShell Web Access Installation via PowerShell Script Block

Pivot detection · T1059.001 · 9 related

Changelog

v2
Candidate ingested via manual entry.2026-07-31
v1
No changelog recorded for this version.2026-07-30

Detection content is published as a reviewed draft. Tune thresholds and exclusions against your own telemetry before enabling this rule for alerting.

windows-powershell-script-installs-and-configures-powershell-web-access-pswa-5f9c7f1a

title: Windows PowerShell Web Access Installation via PowerShell Script Block
id: ce0e85f5-dcd3-4158-ab75-039a44bf32ba
status: test
description: This rule identifies PowerShell activity that installs PowerShell Web Access and configures a web application and authorization rules. An attacker could use this to establish remote web-based access paths that may support persistence or follow-on abuse. The detection relies on ScriptBlockText content from PowerShell script block logging, matching installation, application setup, and authorization rule commands.
references:
  - https://docs.microsoft.com/en-us/powershell/module/powershellwebaccess/install-pswawebapplication
  - https://www.cisa.gov/news-events/cybersecurity-advisories/aa24-241a
  - https://gist.github.com/MHaggis/7e67b659af9148fa593cf2402edebb41
  - https://github.com/SigmaHQ/sigma/blob/master/rules/windows/powershell/powershell_script/posh_ps_powershell_web_access_installation.yml
author: Michael Haag, Huntrule Team
date: 2024-09-03
tags:
  - attack.persistence
  - attack.execution
  - attack.t1059.001
logsource:
  product: windows
  category: ps_script
  definition: "Requirements: Script Block Logging must be enabled"
detection:
  selection_install:
    ScriptBlockText|contains: Install-WindowsFeature WindowsPowerShellWebAccess
  selection_config:
    ScriptBlockText|contains: Install-PswaWebApplication
  selection_auth:
    ScriptBlockText|contains|all:
      - Add-PswaAuthorizationRule
      - -UserName *
      - -ComputerName *
  condition: 1 of selection_*
falsepositives:
  - Legitimate PowerShell Web Access installations by administrators
level: high
license: DRL-1.1
related:
  - id: 5f9c7f1a-7c21-4c39-b2f3-8d8006e0e51f
    type: derived

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