Windows RDP Tunneling Using plink.exe on Local Port 3389
Alert on plink.exe command lines referencing 127.0.0.1:3389 or port 3389, suggesting potential RDP tunneling on Windows.
- Product
- windows
- Category
- process_creation
- Author
- Florian Roth (Nextron Systems) (SigmaHQ), DRL 1.1
- Published
- 2022-08-04
- Updated
- 2026-07-30
ATT&CK techniques
C2Recon
Resource Dev
Initial Access
Execution
Persistence
Priv Esc
Defense Evasion
Cred Access
Discovery
Lateral Movement
Collection
Exfiltration
Impact
What it detects
This rule flags process creation where plink.exe is invoked with command-line arguments indicating an RDP-related local port connection to 127.0.0.1:3389 or a generic 3389 usage. Attackers can use plink to create stealthy network tunneling paths that blend into legitimate tooling and bypass simpler egress or access controls. Telemetry required is Windows process creation events capturing the full image path and command line for plink.exe.
Reporting behind it
Detection content is published as a reviewed draft. Tune thresholds and exclusions against your own telemetry before enabling this rule for alerting.
title: Windows RDP Tunneling Using plink.exe on Local Port 3389
id: bed4d332-b5f7-4033-9d6d-d94f918743ba
related:
- id: f7d7ebd5-a016-46e2-9c54-f9932f2d386d
type: similar
- id: f38ce0b9-5e97-4b47-a211-7dc8d8b871da
type: derived
status: test
description: This rule flags process creation where plink.exe is invoked with command-line arguments indicating an RDP-related local port connection to 127.0.0.1:3389 or a generic 3389 usage. Attackers can use plink to create stealthy network tunneling paths that blend into legitimate tooling and bypass simpler egress or access controls. Telemetry required is Windows process creation events capturing the full image path and command line for plink.exe.
references:
- https://www.microsoft.com/security/blog/2022/07/26/malicious-iis-extensions-quietly-open-persistent-backdoors-into-servers/
- https://github.com/SigmaHQ/sigma/blob/master/rules/windows/process_creation/proc_creation_win_plink_susp_tunneling.yml
author: Florian Roth (Nextron Systems), Huntrule Team
date: 2022-08-04
modified: 2023-01-27
tags:
- attack.command-and-control
- attack.t1572
logsource:
category: process_creation
product: windows
detection:
selection_a:
Image|endswith: \plink.exe
CommandLine|contains: :127.0.0.1:3389
selection_b1:
Image|endswith: \plink.exe
CommandLine|contains: :3389
selection_b2:
CommandLine|contains:
- " -P 443"
- " -P 22"
condition: selection_a or all of selection_b*
falsepositives:
- Unknown
level: high
license: DRL-1.1