Potential SSH Tunnel Persistence Install Using A Scheduled Task — Sigma Rule

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

title: Potential SSH Tunnel Persistence Install Using A Scheduled Task
id: 2daa93a0-a5fb-41c5-8cd8-3c11294bfd1f
status: experimental
description: Detects the creation of new scheduled tasks via commandline, using Schtasks.exe. This rule detects tasks creating that call OpenSSH, which may indicate the creation of reverse SSH tunnel to the attacker's server.
references:
    - https://thedfirreport.com/2023/10/30/netsupport-intrusion-results-in-domain-compromise/
    - https://www.kroll.com/en/insights/publications/cyber/cactus-ransomware-prickly-new-variant-evades-detection
author: Rory Duncan
date: 2025-07-14
tags:
    - attack.privilege-escalation
    - attack.persistence
    - attack.execution
    - attack.t1053.005
    - attack.command-and-control
logsource:
    product: windows
    category: process_creation
detection:
    selection_img:
        - Image|endswith: '\schtasks.exe'
        - OriginalFileName: 'schtasks.exe'
    selection_cli_sshd:
        CommandLine|contains|all:
            - ' /create '
            - 'sshd.exe'
            - '-f'
    selection_cli_ssh:
        CommandLine|contains|all:
            - ' /create '
            - 'ssh.exe'
            - '-i'
    condition: selection_img and 1 of selection_cli_*
falsepositives:
    - Unknown
level: high