Windows: ssh.exe RDP tunneling to :3389 via SSH

Alerts on Windows process executions of ssh.exe that reference RDP port :3389 for SSH tunneling.

FreeUnreviewedSigmahighv1

windows-ssh-exe-rdp-tunneling-to-3389-via-ssh-f7d7ebd5

title: "Windows: ssh.exe RDP tunneling to :3389 via SSH"
id: a9bfbc5f-f609-4ab9-8354-a9abbe1cec74
related:
  - id: f38ce0b9-5e97-4b47-a211-7dc8d8b871da
    type: similar
  - id: f7d7ebd5-a016-46e2-9c54-f9932f2d386d
    type: derived
status: test
description: This rule flags process executions where ssh.exe is launched and the command line includes ':3389', which is commonly used for RDP port targeting. Attackers may use SSH tunneling to route RDP-related traffic through an approved or less-monitored channel, helping evade network controls. The detection relies on Windows process creation telemetry, specifically the image path ending with '\ssh.exe' and the presence of ':3389' in the command line.
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_rdp_tunneling.yml
author: Nasreddine Bencherchali (Nextron Systems), Huntrule Team
date: 2022-10-12
modified: 2023-01-25
tags:
  - attack.command-and-control
  - attack.t1572
logsource:
  category: process_creation
  product: windows
detection:
  selection:
    Image|endswith: \ssh.exe
    CommandLine|contains: :3389
  condition: selection
falsepositives:
  - Unknown
level: high
license: DRL-1.1

What it detects

This rule flags process executions where ssh.exe is launched and the command line includes ':3389', which is commonly used for RDP port targeting. Attackers may use SSH tunneling to route RDP-related traffic through an approved or less-monitored channel, helping evade network controls. The detection relies on Windows process creation telemetry, specifically the image path ending with '\ssh.exe' and the presence of ':3389' in the command line.

Known false positives

Unknown

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