OpenSSH >= 2.3.0 AllowTcpForwarding Port Bouncing

medium Nessus Plugin ID 17744
New! Plugin Severity Now Using CVSS v3

The calculated severity for Plugins has been updated to use CVSS v3 by default. Plugins that do not have a CVSS v3 score will fall back to CVSS v2 for calculating severity. Severity display preferences can be toggled in the settings dropdown.


The remote SSH server may permit anonymous port bouncing.


According to its banner, the remote host is running OpenSSH, version 2.3.0 or later. Such versions of OpenSSH allow forwarding TCP connections. If the OpenSSH server is configured to allow anonymous connections (e.g. AnonCVS), remote, unauthenticated users could use the host as a proxy.


Disallow anonymous users, set AllowTcpForwarding to 'no', or use the Match directive to restrict anonymous users.

See Also

Plugin Details

Severity: Medium

ID: 17744

File Name: openssh_tcp_forwarding.nasl

Version: 1.4

Type: remote

Family: Misc.

Published: 12/1/2011

Updated: 11/15/2018

Dependencies: ssh_detect.nasl

Risk Information


Risk Factor: Low

Score: 3.7


Risk Factor: Medium

Base Score: 6.4

Vector: AV:N/AC:L/Au:N/C:P/I:P/A:N

Vulnerability Information

CPE: cpe:/a:openbsd:openssh

Vulnerability Publication Date: 8/21/2004

Reference Information

CVE: CVE-2004-1653