New Port Forwarding Rule Added Via Netsh.EXE — Sigma Rule

Rule metadata and linked tags

Author: Florian Roth (Nextron Systems), omkar72, oscd.community, Swachchhanda Shrawan Poudel. Source status: test; severity: medium. Source dates: 2019-01-29 / 2023-09-01.

{
  "category": "process_creation",
  "product": "windows"
}

Pinned original Sigma rule · Detection Rule License 1.1

Source SHA-256: 99793e40ac1f54c17874beb4e2659749a3882598fe0e7cf93d4621127bd65a38

Detection logic

Original source YAML. Source-tag agreement is not proof of complete semantic coverage. This rule has not been compiled for a SIEM backend or validated against live telemetry here.

title: New Port Forwarding Rule Added Via Netsh.EXE
id: 322ed9ec-fcab-4f67-9a34-e7c6aef43614
status: test
description: Detects the execution of netsh commands that configure a new port forwarding (PortProxy) rule
references:
    - https://www.fireeye.com/blog/threat-research/2019/01/bypassing-network-restrictions-through-rdp-tunneling.html
    - https://adepts.of0x.cc/netsh-portproxy-code/
    - https://www.dfirnotes.net/portproxy_detection/
author: Florian Roth (Nextron Systems), omkar72, oscd.community, Swachchhanda Shrawan Poudel
date: 2019-01-29
modified: 2023-09-01
tags:
    - attack.lateral-movement
    - attack.command-and-control
    - attack.t1090
logsource:
    category: process_creation
    product: windows
detection:
    selection_img:
        - Image|endswith: '\netsh.exe'
        - OriginalFileName: 'netsh.exe'
    selection_cli_1:
        CommandLine|contains|all:
            - 'interface'
            - 'portproxy'
            - 'add'
            - 'v4tov4'
    selection_cli_2:
        CommandLine|contains|all:
            # Example: netsh I p a v l=8001 listena=127.0.0.1 connectp=80 c=192.168.1.1
            - 'i ' # interface
            - 'p ' # portproxy
            - 'a ' # add
            - 'v ' # v4tov4
    selection_cli_3:
        CommandLine|contains|all:
            - 'connectp'
            - 'listena'
            - 'c='
    condition: selection_img and 1 of selection_cli_*
falsepositives:
    - Legitimate administration activity
    - WSL2 network bridge PowerShell script used for WSL/Kubernetes/Docker (e.g. https://github.com/microsoft/WSL/issues/4150#issuecomment-504209723)
level: medium

Original YAML and metadata in JSON

False positives

• Legitimate administration activity
• WSL2 network bridge PowerShell script used for WSL/Kubernetes/Docker (e.g. https://github.com/microsoft/WSL/issues/4150#issuecomment-504209723)

Source references

• https://www.fireeye.com/blog/threat-research/2019/01/bypassing-network-restrictions-through-rdp-tunneling.html
• https://adepts.of0x.cc/netsh-portproxy-code/
• https://www.dfirnotes.net/portproxy_detection/