PowerShell: Signed UtilityFunctions.ps1 Loading Managed DLL via Proxy Execution

ATT&CK techniques

Defense Evasion

Recon
Resource Dev
Initial Access
Execution
Persistence
Priv Esc
Defense Evasion
- T1216System Script Proxy Execution
Cred Access
Discovery
Lateral Movement
Collection
C2
Exfiltration
Impact

What it detects

This rule matches PowerShell process command lines that include UtilityFunctions.ps1 and the string "RegSnapin ", indicating proxy-style loading of a managed DLL from a Microsoft signed script. Attackers can use signed utility scripts to blend into legitimate activity while executing or side-loading malicious functionality via .NET assemblies. It relies on Windows process creation telemetry, specifically the PowerShell command-line content.

Reporting behind it

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PowerShell: Signed UtilityFunctions.ps1 Loading Managed DLL via Proxy Execution

Pivot detection · T1216 · 9 related

Changelog

v2

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-utilityfunctions-ps1-loading-managed-dll-via-proxy-0403d67d

title: "PowerShell: Signed UtilityFunctions.ps1 Loading Managed DLL via Proxy Execution"
id: a86beccb-2e9f-4052-8e32-84e8f526f925
status: test
description: This rule matches PowerShell process command lines that include UtilityFunctions.ps1 and the string "RegSnapin ", indicating proxy-style loading of a managed DLL from a Microsoft signed script. Attackers can use signed utility scripts to blend into legitimate activity while executing or side-loading malicious functionality via .NET assemblies. It relies on Windows process creation telemetry, specifically the PowerShell command-line content.
references:
  - https://lolbas-project.github.io/lolbas/Scripts/UtilityFunctions/
  - https://github.com/SigmaHQ/sigma/blob/master/rules/windows/process_creation/proc_creation_win_lolbin_utilityfunctions.yml
author: frack113, Huntrule Team
date: 2022-05-28
tags:
  - attack.stealth
  - attack.t1216
logsource:
  category: process_creation
  product: windows
detection:
  selection:
    CommandLine|contains:
      - UtilityFunctions.ps1
      - "RegSnapin "
  condition: selection
falsepositives:
  - Unknown
level: medium
license: DRL-1.1
related:
  - id: 0403d67d-6227-4ea8-8145-4e72db7da120
    type: derived

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