PowerShell ScriptBlock Logging: Obfuscated RUNDLL Launcher using rundll32.exe and shell32.dll

Identifies PowerShell script content invoking rundll32.exe/shell32.dll via shellexec_rundll and referencing PowerShell.

FreeReviewedSigma · Medium · v2

Product: windows
Category: ps_script
Author: Timur Zinniatullin, oscd.community (SigmaHQ), DRL 1.1
Published: 2020-10-18
Updated: 2026-07-31

ATT&CK techniques

Execution → Defense Evasion

Recon
Resource Dev
Initial Access
Execution
- T1059.001PowerShell
Persistence
Priv Esc
Defense Evasion
- T1027Obfuscated Files or Information
Cred Access
Discovery
Lateral Movement
Collection
C2
Exfiltration
Impact

What it detects

This rule flags PowerShell script content containing all required strings associated with a RUNDLL launcher technique: rundll32.exe, shell32.dll, shellexec_rundll, and powershell. Attackers may use this pattern to obscure execution paths and launch PowerShell indirectly via Windows library-based execution. The detection relies on Script Block Logging telemetry that provides the full PowerShell ScriptBlockText for string matching.

Reporting behind it

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Suspicious PEAKLIGHT Memory-Only PowerShell Downloader Flags (via process_creation)

Obfuscated PowerShell Script: Indirect Cmdlet Execution via ExportedCommands Array Index

PowerShell ScriptBlock Logging: Obfuscated RUNDLL Launcher using rundll32.exe and shell32.dll

Pivot detection · T1027 · 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.

obfuscated-powershell-execution-via-rundll32-launcher-windows-powershell-script-e6cb92b4

title: "PowerShell ScriptBlock Logging: Obfuscated RUNDLL Launcher using rundll32.exe and shell32.dll"
id: ead596d8-87e9-403d-8542-f50b1681cb40
status: test
description: "This rule flags PowerShell script content containing all required strings associated with a RUNDLL launcher technique: rundll32.exe, shell32.dll, shellexec_rundll, and powershell. Attackers may use this pattern to obscure execution paths and launch PowerShell indirectly via Windows library-based execution. The detection relies on Script Block Logging telemetry that provides the full PowerShell ScriptBlockText for string matching."
references:
  - https://github.com/SigmaHQ/sigma/issues/1009
  - https://github.com/SigmaHQ/sigma/blob/master/rules/windows/powershell/powershell_script/posh_ps_invoke_obfuscation_via_rundll.yml
author: Timur Zinniatullin, oscd.community, Huntrule Team
date: 2020-10-18
modified: 2022-11-29
tags:
  - attack.stealth
  - attack.t1027
  - attack.execution
  - attack.t1059.001
logsource:
  product: windows
  category: ps_script
  definition: "Requirements: Script Block Logging must be enabled"
detection:
  selection_4104:
    ScriptBlockText|contains|all:
      - rundll32.exe
      - shell32.dll
      - shellexec_rundll
      - powershell
  condition: selection_4104
falsepositives:
  - Unknown
level: medium
license: DRL-1.1
related:
  - id: e6cb92b4-b470-4eb8-8a9d-d63e8583aae0
    type: derived

Convert

This rule as a query you can run. Uses no unlock credit.

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