PUA - NPS Tunneling Tool Execution

Hunt Hypothesis

Detects the use of NPS, a port forwarding and intranet penetration proxy server

Detection Rule

Sigma (Original)

title: PUA - NPS Tunneling Tool Execution
id: 68d37776-61db-42f5-bf54-27e87072d17e
status: test
description: Detects the use of NPS, a port forwarding and intranet penetration proxy server
references:
    - https://github.com/ehang-io/nps
author: Florian Roth (Nextron Systems)
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:
        # v0.26.10
        Hashes|contains:
            - "MD5=AE8ACF66BFE3A44148964048B826D005"
            - "SHA1=CEA49E9B9B67F3A13AD0BE1C2655293EA3C18181"
            - "SHA256=5A456283392FFCEEEACA3D3426C306EB470304637520D72FED1CC1FEBBBD6856"
    condition: 1 of selection_*
falsepositives:
    - Legitimate use
level: high

KQL (Azure Sentinel)

imProcessCreate
| where TargetProcessName endswith "\\npc.exe" or (TargetProcessCommandLine contains " -server=" and TargetProcessCommandLine contains " -vkey=" and TargetProcessCommandLine contains " -password=") or TargetProcessCommandLine contains " -config=npc" or (TargetProcessMD5 startswith "AE8ACF66BFE3A44148964048B826D005" or TargetProcessSHA1 startswith "CEA49E9B9B67F3A13AD0BE1C2655293EA3C18181" or TargetProcessSHA256 startswith "5A456283392FFCEEEACA3D3426C306EB470304637520D72FED1CC1FEBBBD6856")

Required Data Sources

False Positive Guidance

• Legitimate use

MITRE ATT&CK Context

• Tactic: Command and Control
• Technique: T1090 — T1090

References

• https://github.com/ehang-io/nps
• SigmaHQ Rule