Port Forwarding via SSH.EXE on Windows

Flags Windows executions of ssh.exe using remote port forwarding (-R) based on process creation command-line content.

FreeUnreviewedSigmamediumv1

port-forwarding-via-ssh-exe-on-windows-327f48c1

title: Port Forwarding via SSH.EXE on Windows
id: f549061c-82c1-43e7-a0ce-f36f8669aa5d
status: test
description: This rule flags process executions of ssh.exe where the command line includes a remote port forwarding argument (-R). Attackers can use SSH port forwarding to route traffic through an affected host for command-and-control or lateral movement. Telemetry relies on Windows process creation events, specifically the image path ending with \ssh.exe and matching command-line text containing ' -R '.
references:
  - https://www.absolomb.com/2018-01-26-Windows-Privilege-Escalation-Guide/
  - https://github.com/SigmaHQ/sigma/blob/master/rules/windows/process_creation/proc_creation_win_ssh_port_forward.yml
author: Nasreddine Bencherchali (Nextron Systems), Huntrule Team
date: 2022-10-12
modified: 2024-03-05
tags:
  - attack.command-and-control
  - attack.lateral-movement
  - attack.t1572
  - attack.t1021.001
  - attack.t1021.004
logsource:
  category: process_creation
  product: windows
detection:
  selection:
    Image|endswith: \ssh.exe
    CommandLine|contains|windash: " -R "
  condition: selection
falsepositives:
  - Administrative activity using a remote port forwarding to a local port
level: medium
license: DRL-1.1
related:
  - id: 327f48c1-a6db-4eb8-875a-f6981f1b0183
    type: derived

What it detects

This rule flags process executions of ssh.exe where the command line includes a remote port forwarding argument (-R). Attackers can use SSH port forwarding to route traffic through an affected host for command-and-control or lateral movement. Telemetry relies on Windows process creation events, specifically the image path ending with \ssh.exe and matching command-line text containing ' -R '.

Known false positives

Administrative activity using a remote port forwarding to a local port

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