Windows: NPS (npc.exe) Port Forwarding Proxy Execution via Command-Line Parameters

title: "Windows: NPS (npc.exe) Port Forwarding Proxy Execution via Command-Line Parameters"
id: 5e12dcb4-c407-463e-8723-605f9d7bff93
status: test
description: This rule identifies execution of the NPS tunneling/port-forwarding tool by matching process creations where the image ends with npc.exe and the command line includes NPS-specific server and credential options. It also flags instances using an NPS configuration parameter (" -config=npc"). Such behavior matters because NPS can enable intranet penetration and covert traffic forwarding, and the detection relies on Windows process creation telemetry including image name, full command line, and (optionally) known hashes.
references:
  - https://github.com/ehang-io/nps
  - https://github.com/SigmaHQ/sigma/blob/master/rules/windows/process_creation/proc_creation_win_pua_nps.yml
author: Florian Roth (Nextron Systems), Huntrule Team
date: 2022-10-08
modified: 2024-11-23
tags:
  - attack.command-and-control
  - attack.t1090
logsource:
  category: process_creation
  product: windows
detection:
  selection_img:
    Image|endswith: \npc.exe
  selection_cli_1:
    CommandLine|contains|all:
      - " -server="
      - " -vkey="
      - " -password="
  selection_cli_2:
    CommandLine|contains: " -config=npc"
  selection_hashes:
    Hashes|contains:
      - MD5=AE8ACF66BFE3A44148964048B826D005
      - SHA1=CEA49E9B9B67F3A13AD0BE1C2655293EA3C18181
      - SHA256=5A456283392FFCEEEACA3D3426C306EB470304637520D72FED1CC1FEBBBD6856
  condition: 1 of selection_*
falsepositives:
  - Legitimate use
level: high
license: DRL-1.1
related:
  - id: 68d37776-61db-42f5-bf54-27e87072d17e
    type: derived