Windows PowerShell Script Block Matches Common Reflection and Injection Keywords

Alerts on PowerShell script block text containing reflection, dynamic assembly loading, and injection-related keywords.

FreeReviewedSigma · Medium · v2

Product: windows
Category: ps_script
Author: Florian Roth (Nextron Systems), Perez Diego (@darkquassar), Tuan Le (NCSGroup) (SigmaHQ), DRL 1.1
Published: 2019-02-11
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 flags PowerShell script block content containing specific .NET reflection, assembly loading, interop, and injection-related keywords often seen in exploitation frameworks. Attackers may use these constructs to load assemblies dynamically, resolve unmanaged functions, or perform execution and process manipulation within PowerShell. It relies on telemetry that captures PowerShell script block text, such as Script Block Logging, and matches on substring presence for the listed patterns.

Reporting behind it

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Windows PowerShell Script Block Matches Common Reflection and Injection Keywords

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-block-keyword-matches-for-suspicious-reflection-and-in-1f49f2ab

title: Windows PowerShell Script Block Matches Common Reflection and Injection Keywords
id: b1c55a72-8de9-496e-b3ff-bf427b3b46d5
status: test
description: This rule flags PowerShell script block content containing specific .NET reflection, assembly loading, interop, and injection-related keywords often seen in exploitation frameworks. Attackers may use these constructs to load assemblies dynamically, resolve unmanaged functions, or perform execution and process manipulation within PowerShell. It relies on telemetry that captures PowerShell script block text, such as Script Block Logging, and matches on substring presence for the listed patterns.
references:
  - https://posts.specterops.io/entering-a-covenant-net-command-and-control-e11038bcf462
  - https://github.com/PowerShellMafia/PowerSploit/blob/d943001a7defb5e0d1657085a77a0e78609be58f/CodeExecution/Invoke-ReflectivePEInjection.ps1
  - https://github.com/hlldz/Phant0m/blob/30c2935d8cf4aafda17ee2fab7cd0c4aa9a607c2/old/Invoke-Phant0m.ps1
  - https://gist.github.com/MHaggis/0dbe00ad401daa7137c81c99c268cfb7
  - https://github.com/SigmaHQ/sigma/blob/master/rules/windows/powershell/powershell_script/posh_ps_susp_keywords.yml
author: Florian Roth (Nextron Systems), Perez Diego (@darkquassar), Tuan Le (NCSGroup), Huntrule Team
date: 2019-02-11
modified: 2023-04-21
tags:
  - attack.execution
  - attack.t1059.001
logsource:
  product: windows
  category: ps_script
  definition: "Requirements: Script Block Logging must be enabled"
detection:
  selection:
    ScriptBlockText|contains:
      - System.Reflection.Assembly.Load($
      - "[System.Reflection.Assembly]::Load($"
      - "[Reflection.Assembly]::Load($"
      - System.Reflection.AssemblyName
      - Reflection.Emit.AssemblyBuilderAccess
      - Reflection.Emit.CustomAttributeBuilder
      - Runtime.InteropServices.UnmanagedType
      - Runtime.InteropServices.DllImportAttribute
      - SuspendThread
      - rundll32
  condition: selection
falsepositives:
  - Unknown
level: medium
license: DRL-1.1
related:
  - id: 1f49f2ab-26bc-48b3-96cc-dcffbc93eadf
    type: derived

Convert

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