Windows PowerShell User Agent — Sigma Rule

Rule metadata and linked tags

Author: Florian Roth (Nextron Systems). Source status: test; severity: medium. Source dates: 2017-03-13 / 2021-11-27.

{
  "category": "proxy"
}

Pinned original Sigma rule · Detection Rule License 1.1

Source SHA-256: cdb99d489966b9099ccc2c590d9908cad6df21c6ffc4f9eca97d6c25700a29f3

Detection logic

Original source YAML. Source-tag agreement is not proof of complete semantic coverage. This rule has not been compiled for a SIEM backend or validated against live telemetry here.

title: Windows PowerShell User Agent
id: c8557060-9221-4448-8794-96320e6f3e74
status: test
description: Detects Windows PowerShell Web Access
references:
    - https://msdn.microsoft.com/powershell/reference/5.1/microsoft.powershell.utility/Invoke-WebRequest
author: Florian Roth (Nextron Systems)
date: 2017-03-13
modified: 2021-11-27
tags:
    - attack.command-and-control
    - attack.t1071.001
logsource:
    category: proxy
detection:
    selection:
        c-useragent|contains: ' WindowsPowerShell/'
    condition: selection
falsepositives:
    - Administrative scripts that download files from the Internet
    - Administrative scripts that retrieve certain website contents
level: medium

Original YAML and metadata in JSON

False positives

• Administrative scripts that download files from the Internet
• Administrative scripts that retrieve certain website contents

Source references

• https://msdn.microsoft.com/powershell/reference/5.1/microsoft.powershell.utility/Invoke-WebRequest