Suspicious PowerShell Invocations - Specific


Description

Detects suspicious PowerShell invocation command parameters

Query · sigma

selection_convert_b64:
  ScriptBlockText|contains|all:
  - -nop
  - ' -w '
  - hidden
  - ' -c '
  - '[Convert]::FromBase64String'
selection_iex_selection:
  ScriptBlockText|contains|all:
  - ' -w '
  - hidden
  - -noni
  - -nop
  - ' -c '
  - iex
  - New-Object
selection_enc_selection:
  ScriptBlockText|contains|all:
  - ' -w '
  - hidden
  - -ep
  - bypass
  - -Enc
selection_reg_selection:
  ScriptBlockText|contains|all:
  - powershell
  - reg
  - add
  ScriptBlockText|contains:
  - \software\microsoft\windows\currentversion\run
  - \software\wow6432node\microsoft\windows\currentversion\run
  - \software\microsoft\windows\currentversion\policies\explorer\run
selection_webclient_selection:
  ScriptBlockText|contains|all:
  - bypass
  - -noprofile
  - -windowstyle
  - hidden
  - new-object
  - system.net.webclient
  - .download
selection_iex_webclient:
  ScriptBlockText|contains|all:
  - iex
  - New-Object
  - Net.WebClient
  - .Download
filter_chocolatey:
  ScriptBlockText|contains:
  - (New-Object System.Net.WebClient).DownloadString('https://community.chocolatey.org/install.ps1
  - (New-Object System.Net.WebClient).DownloadString('https://chocolatey.org/install.ps1')
  - Write-ChocolateyWarning
condition: 1 of selection_* and not 1 of filter_*

Known false positives

  • Unknown
Raw source Suspicious PowerShell Invocations - Specific · Sigma
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Published by SigmaHQ/sigma ↗, licensed under Detection Rule License 1.1 ↗. Reproduced here unmodified.
title: Suspicious PowerShell Invocations - Specific
id: ae7fbf8e-f3cb-49fd-8db4-5f3bed522c71
related:
    - id: fce5f582-cc00-41e1-941a-c6fabf0fdb8c
      type: obsolete
    - id: 8ff28fdd-e2fa-4dfa-aeda-ef3d61c62090
      type: similar
    - id: 536e2947-3729-478c-9903-745aaffe60d2
      type: similar
status: test
description: Detects suspicious PowerShell invocation command parameters
references:
    - Internal Research
    - https://github.com/HackTricks-wiki/hacktricks/blob/e4c7b21b8f36c97c35b7c622732b38a189ce18f7/src/windows-hardening/windows-local-privilege-escalation/privilege-escalation-with-autorun-binaries.md
author: Florian Roth (Nextron Systems), Jonhnathan Ribeiro
date: 2017-03-05
modified: 2025-02-17
tags:
    - attack.execution
    - attack.t1059.001
logsource:
    product: windows
    category: ps_script
    definition: 'Requirements: Script Block Logging must be enabled'
detection:
    selection_convert_b64:
        ScriptBlockText|contains|all:
            - '-nop'
            - ' -w '
            - 'hidden'
            - ' -c '
            - '[Convert]::FromBase64String'
    selection_iex_selection:
        ScriptBlockText|contains|all:
            - ' -w '
            - 'hidden'
            - '-noni'
            - '-nop'
            - ' -c '
            - 'iex'
            - 'New-Object'
    selection_enc_selection:
        ScriptBlockText|contains|all:
            - ' -w '
            - 'hidden'
            - '-ep'
            - 'bypass'
            - '-Enc'
    selection_reg_selection:
        ScriptBlockText|contains|all:
            - 'powershell'
            - 'reg'
            - 'add'
        ScriptBlockText|contains:
            - '\software\microsoft\windows\currentversion\run'
            - '\software\wow6432node\microsoft\windows\currentversion\run'
            - '\software\microsoft\windows\currentversion\policies\explorer\run'
    selection_webclient_selection:
        ScriptBlockText|contains|all:
            - 'bypass'
            - '-noprofile'
            - '-windowstyle'
            - 'hidden'
            - 'new-object'
            - 'system.net.webclient'
            - '.download'
    selection_iex_webclient:
        ScriptBlockText|contains|all:
            - 'iex'
            - 'New-Object'
            - 'Net.WebClient'
            - '.Download'
    filter_chocolatey:
        ScriptBlockText|contains:
            - "(New-Object System.Net.WebClient).DownloadString('https://community.chocolatey.org/install.ps1"
            - "(New-Object System.Net.WebClient).DownloadString('https://chocolatey.org/install.ps1')"
            - 'Write-ChocolateyWarning'
    condition: 1 of selection_* and not 1 of filter_*
falsepositives:
    - Unknown
level: high

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