Windows Process Creation: cmd.exe Launching with PowerShell in .lnk Link Command

Alerts when explorer launches cmd.exe with command lines containing both PowerShell and a .lnk reference.

FreeUnreviewedSigmamediumv1

windows-process-creation-cmd-exe-launching-with-powershell-in-lnk-link-command-30e92f50

title: "Windows Process Creation: cmd.exe Launching with PowerShell in .lnk Link Command"
id: 6c53aa01-3f90-4b94-b3df-4310dd34b8bf
status: test
description: This rule flags process creation events where cmd.exe is started by explorer.exe and the command line contains both 'powershell' and '.lnk'. Attackers often embed PowerShell execution in shortcut (.lnk) link content to trigger script execution on user interaction. Telemetry relies on Windows process creation logging that includes the parent process image, the child process image, and the full command line.
references:
  - https://www.x86matthew.com/view_post?id=embed_exe_lnk
  - https://github.com/SigmaHQ/sigma/blob/master/rules/windows/process_creation/proc_creation_win_susp_embed_exe_lnk.yml
author: frack113, Huntrule Team
date: 2022-02-06
tags:
  - attack.execution
  - attack.t1059.001
logsource:
  category: process_creation
  product: windows
detection:
  selection:
    ParentImage: C:\Windows\explorer.exe
    Image: C:\Windows\System32\cmd.exe
    CommandLine|contains|all:
      - powershell
      - .lnk
  condition: selection
falsepositives:
  - Legitimate commands in .lnk files
level: medium
license: DRL-1.1
related:
  - id: 30e92f50-bb5a-4884-98b5-d20aa80f3d7a
    type: derived

What it detects

This rule flags process creation events where cmd.exe is started by explorer.exe and the command line contains both 'powershell' and '.lnk'. Attackers often embed PowerShell execution in shortcut (.lnk) link content to trigger script execution on user interaction. Telemetry relies on Windows process creation logging that includes the parent process image, the child process image, and the full command line.

Known false positives

Legitimate commands in .lnk files

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