Change PowerShell Policies to an Insecure Level — Sigma Rule

Rule metadata and linked tags

Author: frack113. Source status: test; severity: medium. Source dates: 2021-11-01 / 2025-10-07.

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

Pinned original Sigma rule · Detection Rule License 1.1

Source SHA-256: 6fde98ed6d74d24b62f202e8e39e933a3fd396a292b6834ab06c4ecef1ccf5be

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: Change PowerShell Policies to an Insecure Level
id: 87e3c4e8-a6a8-4ad9-bb4f-46e7ff99a180
related:
    - id: cf2e938e-9a3e-4fe8-a347-411642b28a9f # ProcCreation Registry
      type: similar
    - id: 61d0475c-173f-4844-86f7-f3eebae1c66b # ScriptBlock
      type: similar
    - id: fad91067-08c5-4d1a-8d8c-d96a21b37814 # Registry
      type: similar
status: test
description: Detects changing the PowerShell script execution policy to a potentially insecure level using the "-ExecutionPolicy" flag.
references:
    - https://learn.microsoft.com/en-us/powershell/module/microsoft.powershell.security/set-executionpolicy?view=powershell-7.4
    - https://learn.microsoft.com/en-us/powershell/module/microsoft.powershell.core/about/about_execution_policies?view=powershell-7.4
    - https://adsecurity.org/?p=2604
    - https://thedfirreport.com/2021/11/01/from-zero-to-domain-admin/
author: frack113
date: 2021-11-01
modified: 2025-10-07
tags:
    - attack.execution
    - attack.t1059.001
logsource:
    product: windows
    category: process_creation
detection:
    selection_img:
        - OriginalFileName:
              - 'powershell_ise.exe'
              - 'PowerShell.EXE'
              - 'pwsh.dll'
        - Image|endswith:
              - '\powershell_ise.exe'
              - '\powershell.exe'
              - '\pwsh.exe'
    selection_option:
        CommandLine|contains:
            - '-executionpolicy '
            - ' -ep '
            - ' -exec '
    selection_level:
        CommandLine|contains:
            - 'Bypass'
            - 'Unrestricted'
    filter_main_powershell_core:
        ParentImage:
            - 'C:\Windows\SysWOW64\msiexec.exe'
            - 'C:\Windows\System32\msiexec.exe'
        CommandLine|contains:
            - '-NoProfile -ExecutionPolicy Bypass -File "C:\Program Files\PowerShell\7\'
            - '-NoProfile -ExecutionPolicy Bypass -File "C:\Program Files (x86)\PowerShell\7\'
    filter_optional_avast:
        ParentImage|contains:
            - 'C:\Program Files\Avast Software\Avast\'
            - 'C:\Program Files (x86)\Avast Software\Avast\'
            - '\instup.exe'
        CommandLine|contains:
            - '-ExecutionPolicy ByPass -File "C:\Program Files\Avast Software\Avast'
            - '-ExecutionPolicy ByPass -File "C:\Program Files (x86)\Avast Software\Avast\'
    condition: all of selection_* and not 1 of filter_main_* and not 1 of filter_optional_*
falsepositives:
    - Administrator scripts
level: medium

Original YAML and metadata in JSON

False positives

• Administrator scripts

Source references

• https://learn.microsoft.com/en-us/powershell/module/microsoft.powershell.security/set-executionpolicy?view=powershell-7.4
• https://learn.microsoft.com/en-us/powershell/module/microsoft.powershell.core/about/about_execution_policies?view=powershell-7.4
• https://adsecurity.org/?p=2604
• https://thedfirreport.com/2021/11/01/from-zero-to-domain-admin/