Windows Process Creation: PowerShell Command Execution Hidden in DLL Invocation

Flags DLL-invoking Windows binaries whose command lines include PowerShell execution strings.

FreeReviewedSigma · High · v1

Product: windows
Category: process_creation
Author: Markus Neis, Nasreddine Bencherchali (Nextron Systems) (SigmaHQ), DRL 1.1
Published: 2018-08-25
Updated: 2026-07-30

ATT&CK techniques

Defense Evasion

Recon
Resource Dev
Initial Access
Execution
Persistence
Priv Esc
Defense Evasion
- T1218.011Rundll32
Cred Access
Discovery
Lateral Movement
Collection
C2
Exfiltration
Impact

What it detects

This rule identifies Windows processes commonly abused to execute DLLs (e.g., rundll32, regsvr32, regasm, regsvcs, installutil) when their command line contains PowerShell-related strings such as DownloadString, FromBase64String, IEX, Invoke-Expression, or Invoke-Command. Attackers may pass PowerShell payloads through DLL invocation to blend in with legitimate signed binary execution paths. The detection relies on process creation telemetry, matching Image and OriginalFileName with specific DLL-related executables and inspecting the CommandLine for PowerShell command indicators.

Reporting behind it

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Malicious Rundll32 DllRegisterServer Execution From a User-Writable Path (via process_creation)

IMEEX Framework DLL Execution via Rundll32 Loading imaadp (via process_creation)

Suspicious Persistence via pcalua Launching rundll32 Control_RunDLL

Suspicious Rundll32 Executing DLL Start Export With Control Flags

Suspicious Rundll32 Execution of Timestamp-Named DLL

Suspicious Rundll32 Loading DLL from LocalAppData with Short Export (via process_creation)

Windows Process Creation: PowerShell Command Execution Hidden in DLL Invocation

Pivot detection · T1218.011 · 9 related

Detection content is published as a reviewed draft. Tune thresholds and exclusions against your own telemetry before enabling this rule for alerting.

windows-process-creation-powershell-command-execution-hidden-in-dll-invocation-6812a10b

title: "Windows Process Creation: PowerShell Command Execution Hidden in DLL Invocation"
id: cad4364e-f234-4f38-9862-e47e57bdca07
status: test
description: This rule identifies Windows processes commonly abused to execute DLLs (e.g., rundll32, regsvr32, regasm, regsvcs, installutil) when their command line contains PowerShell-related strings such as DownloadString, FromBase64String, IEX, Invoke-Expression, or Invoke-Command. Attackers may pass PowerShell payloads through DLL invocation to blend in with legitimate signed binary execution paths. The detection relies on process creation telemetry, matching Image and OriginalFileName with specific DLL-related executables and inspecting the CommandLine for PowerShell command indicators.
references:
  - https://github.com/p3nt4/PowerShdll/blob/62cfa172fb4e1f7f4ac00ca942685baeb88ff356/README.md
  - https://github.com/SigmaHQ/sigma/blob/master/rules/windows/process_creation/proc_creation_win_susp_powershell_execution_via_dll.yml
author: Markus Neis, Nasreddine Bencherchali (Nextron Systems), Huntrule Team
date: 2018-08-25
modified: 2024-03-07
tags:
  - attack.stealth
  - attack.t1218.011
logsource:
  category: process_creation
  product: windows
detection:
  selection_img:
    - Image|endswith:
        - \InstallUtil.exe
        - \RegAsm.exe
        - \RegSvcs.exe
        - \regsvr32.exe
        - \rundll32.exe
    - OriginalFileName:
        - InstallUtil.exe
        - RegAsm.exe
        - RegSvcs.exe
        - REGSVR32.EXE
        - RUNDLL32.EXE
  selection_cli:
    CommandLine|contains:
      - Default.GetString
      - DownloadString
      - FromBase64String
      - "ICM "
      - "IEX "
      - Invoke-Command
      - Invoke-Expression
  condition: all of selection_*
falsepositives:
  - Unknown
level: high
license: DRL-1.1
related:
  - id: 6812a10b-60ea-420c-832f-dfcc33b646ba
    type: derived

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