huntrule

PowerShell ScriptBlock: Module Content Sets Get-VMRemoteFXPhysicalVideoAdapter Function

Flags PowerShell module content that defines Get-VMRemoteFXPhysicalVideoAdapter in a ScriptBlock, consistent with load-order abuse patterns.

FreeUnreviewedSigmahighv1
title: "PowerShell ScriptBlock: Module Content Sets Get-VMRemoteFXPhysicalVideoAdapter Function"
id: 41e37bdc-a216-4104-a238-7acc4bd1aff8
related:
  - id: a6fc3c46-23b8-4996-9ea2-573f4c4d88c5
    type: similar
  - id: f65e22f9-819e-4f96-9c7b-498364ae7a25
    type: similar
  - id: 38a7625e-b2cb-485d-b83d-aff137d859f4
    type: similar
  - id: cacef8fc-9d3d-41f7-956d-455c6e881bc5
    type: derived
status: test
description: This rule identifies PowerShell script blocks that begin by defining the Get-VMRemoteFXPhysicalVideoAdapter function inside a module content context. Attackers can use PowerShell module creation to influence how a signed or trusted binary later resolves module content, supporting stealthy execution via load-order manipulation. The detection relies on telemetry containing PowerShell ScriptBlockText where the script content starts with the specified function definition.
references:
  - https://github.com/redcanaryco/atomic-red-team/blob/f339e7da7d05f6057fdfcdd3742bfcf365fee2a9/atomics/T1218/T1218.md
  - https://github.com/redcanaryco/AtomicTestHarnesses/blob/7e1e4da116801e3d6fcc6bedb207064577e40572/TestHarnesses/T1218_SignedBinaryProxyExecution/InvokeRemoteFXvGPUDisablementCommand.ps1
  - https://github.com/SigmaHQ/sigma/blob/master/rules/windows/powershell/powershell_script/posh_ps_remotefxvgpudisablement_abuse.yml
author: Nasreddine Bencherchali (Nextron Systems), Huntrule Team
date: 2023-05-09
tags:
  - attack.stealth
  - attack.t1218
logsource:
  product: windows
  category: ps_script
  definition: bade5735-5ab0-4aa7-a642-a11be0e40872
detection:
  selection:
    ScriptBlockText|startswith: function Get-VMRemoteFXPhysicalVideoAdapter {
  condition: selection
falsepositives:
  - Unknown
level: high
license: DRL-1.1

What it detects

This rule identifies PowerShell script blocks that begin by defining the Get-VMRemoteFXPhysicalVideoAdapter function inside a module content context. Attackers can use PowerShell module creation to influence how a signed or trusted binary later resolves module content, supporting stealthy execution via load-order manipulation. The detection relies on telemetry containing PowerShell ScriptBlockText where the script content starts with the specified function definition.

Known false positives

  • Unknown

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