Windows Process Execution Proxy Using SyncInvoke in CL_Invocation.ps1

Alerts on Windows command lines containing "SyncInvoke" consistent with CL_Invocation.ps1 execution proxy behavior.

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windows-process-execution-proxy-using-syncinvoke-in-cl-invocation-ps1-a0459f02

title: Windows Process Execution Proxy Using SyncInvoke in CL_Invocation.ps1
id: a4c157fd-3fce-4fe5-9d01-db630a9e1b0b
status: test
description: This rule flags process executions where the command line contains the function call "SyncInvoke" associated with CL_Invocation.ps1 behavior that proxies execution via System.Diagnostics.Process. Attackers may use this pattern to run code through an execution proxy while blending into normal PowerShell-driven command lines. The detection relies on Windows process creation telemetry and matches command-line text containing "SyncInvoke ".
references:
  - https://lolbas-project.github.io/lolbas/Scripts/Cl_invocation/
  - https://twitter.com/bohops/status/948061991012327424
  - https://github.com/SigmaHQ/sigma/blob/master/rules/windows/process_creation/proc_creation_win_powershell_cl_invocation.yml
author: Nasreddine Bencherchali (Nextron Systems), oscd.community, Natalia Shornikova, Huntrule Team
date: 2020-10-14
modified: 2023-08-17
tags:
  - attack.stealth
  - attack.t1216
logsource:
  category: process_creation
  product: windows
detection:
  selection:
    CommandLine|contains: "SyncInvoke "
  condition: selection
falsepositives:
  - Unknown
level: medium
license: DRL-1.1
related:
  - id: a0459f02-ac51-4c09-b511-b8c9203fc429
    type: derived

What it detects

This rule flags process executions where the command line contains the function call "SyncInvoke" associated with CL_Invocation.ps1 behavior that proxies execution via System.Diagnostics.Process. Attackers may use this pattern to run code through an execution proxy while blending into normal PowerShell-driven command lines. The detection relies on Windows process creation telemetry and matches command-line text containing "SyncInvoke ".

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.