PUA - NPS Tunneling Tool Execution

Status: test
Severity: high
Log source: category process_creation, product windows
Author: Florian Roth (Nextron Systems)
Source: github.com/SigmaHQ/sigma

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

Known false positives

Legitimate use

MITRE ATT&CK coverage

Tactic	Techniques
Command & Control	`T1090` Proxy

Telemetry coverage

Provider	Record / event type
Sysmon	Event ID 1: Process creation

Rule body

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

Stages and Predicates

Stage 0: `condition`

1 of selection_*

Stage 1: `selection_img`

selection_img:
    Image|endswith: '\npc.exe'

Stage 2: `selection_cli_1`

selection_cli_1:
    CommandLine|contains|all:
        - ' -server='
        - ' -vkey='
        - ' -password='

Stage 3: `selection_cli_2`

selection_cli_2:
    CommandLine|contains: ' -config=npc'

Stage 4: `selection_hashes`

selection_hashes:
    Hashes|contains:
        - "MD5=AE8ACF66BFE3A44148964048B826D005"
        - "SHA1=CEA49E9B9B67F3A13AD0BE1C2655293EA3C18181"
        - "SHA256=5A456283392FFCEEEACA3D3426C306EB470304637520D72FED1CC1FEBBBD6856"

Indicators

These rows show field, operator, and value matches.

Field	Kind	Values	Search
`CommandLine`	match	`-config=npc` `-password=` `-server=` `-vkey=`	`field:"CommandLine" kind:match`
`Hashes`	match	`MD5=AE8ACF66BFE3A44148964048B826D005` `SHA1=CEA49E9B9B67F3A13AD0BE1C2655293EA3C18181` `SHA256=5A456283392FFCEEEACA3D3426C306EB470304637520D72FED1CC1FEBBBD6856`	`field:"Hashes" kind:match`
`Image`	ends_with	`\npc.exe`	`field:"Image" kind:ends_with value:"\npc.exe"`

PUA - NPS Tunneling Tool Execution

Known false positives

MITRE ATT&CK coverage

Telemetry coverage

Rule body

Stages and Predicates

Stage 0: condition

Stage 1: selection_img

Stage 2: selection_cli_1

Stage 3: selection_cli_2

Stage 4: selection_hashes

Indicators

Stage 0: `condition`

Stage 1: `selection_img`

Stage 2: `selection_cli_1`

Stage 3: `selection_cli_2`

Stage 4: `selection_hashes`