OpenSSH X11UseLocalhost X11 Forwarding Port Hijacking

This script is Copyright (C) 2011-2013 Tenable Network Security, Inc.


Synopsis :

The remote SSH service may be affected by an X11 forwarding port
hijacking vulnerability.

Description :

According to its banner, the version of SSH installed on the remote
host is older than 5.1 and may allow a local user to hijack the X11
forwarding port. The application improperly sets the 'SO_REUSEADDR'
socket option when the 'X11UseLocalhost' configuration option is
disabled.

Note that most operating systems, when attempting to bind to a port
that has previously been bound with the 'SO_REUSEADDR' option, will
check that either the effective user-id matches the previous bind
(common BSD-derived systems) or that the bind addresses do not overlap
(Linux and Solaris). This is not the case with other operating
systems such as HP-UX.

See also :

http://www.openssh.org/txt/release-5.1

Solution :

Upgrade to OpenSSH version 5.1 or later.

Risk factor :

Low / CVSS Base Score : 1.2
(CVSS2#AV:L/AC:H/Au:N/C:P/I:N/A:N)
CVSS Temporal Score : 1.0
(CVSS2#E:F/RL:OF/RC:C)
Public Exploit Available : true

Family: Misc.

Nessus Plugin ID: 44080 ()

Bugtraq ID: 30339

CVE ID: CVE-2008-3259