Potentially Suspicious Powershell Script Execution From Temp Folder — Sigma Rule

Rule metadata and linked tags

Author: Florian Roth (Nextron Systems), Max Altgelt (Nextron Systems), Tim Shelton. Source status: test; severity: medium. Source dates: 2021-07-14 / 2026-02-17.

{
  "category": "process_creation",
  "product": "windows"
}

Pinned original Sigma rule · Detection Rule License 1.1

Source SHA-256: b1db6cff228d97b94a2c6f73894b3d9e5b294df06a00095bb8318ff771b4e594

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: Potentially Suspicious Powershell Script Execution From Temp Folder
id: a6a39bdb-935c-4f0a-ab77-35f4bbf44d33
status: test
description: Detects a potentially suspicious powershell script executions from temporary folder
references:
    - https://www.microsoft.com/security/blog/2021/07/13/microsoft-discovers-threat-actor-targeting-solarwinds-serv-u-software-with-0-day-exploit/
author: Florian Roth (Nextron Systems), Max Altgelt (Nextron Systems), Tim Shelton
date: 2021-07-14
modified: 2026-02-17
tags:
    - attack.execution
    - attack.t1059.001
logsource:
    category: process_creation
    product: windows
detection:
    selection:
        Image|endswith:
            - '\powershell.exe'
            - '\pwsh.exe'
        CommandLine|contains:
            - '\Windows\Temp'
            - '\Temporary Internet'
            - '\AppData\Local\Temp'
            - '\AppData\Roaming\Temp'
            - '%TEMP%'
            - '%TMP%'
            - '%LocalAppData%\Temp'
    filter_optional_vscode:
        CommandLine|contains: '-WindowStyle hidden -Verb runAs'
    filter_optional_amazon_ec2:
        CommandLine|contains: '\Windows\system32\config\systemprofile\AppData\Local\Temp\Amazon\EC2-Windows\'
    filter_optional_generic:
        CommandLine|contains:
            - ' >'
            - 'Out-File'
            - 'ConvertTo-Json'
    filter_optional_chocolatey_installer:
        ParentImage:
            - 'C:\Windows\System32\Msiexec.exe'
            - 'C:\Windows\SysWOW64\Msiexec.exe'
        Image|endswith: '\powershell.exe'
        CommandLine|contains|all:
            - '-NoProfile -ExecutionPolicy Bypass -Command'
            - 'AppData\Local\Temp\'
            - 'Install-Chocolatey.ps1'
    condition: selection and not 1 of filter_optional_*
falsepositives:
    - Administrative scripts
level: medium

Original YAML and metadata in JSON

False positives

• Administrative scripts

Source references

• https://www.microsoft.com/security/blog/2021/07/13/microsoft-discovers-threat-actor-targeting-solarwinds-serv-u-software-with-0-day-exploit/