Note: This is an archival copy of Security Sun Alert 237444 as previously published on
Latest version of this security advisory is available from as Sun Alert 1019235.1.
Article ID : 1019235.1
Article Type : Sun Alerts (SURE)
Last reviewed : 2010-01-20
Audience : PUBLIC
Copyright Notice: Copyright © 2010, Oracle Corporation and/or its affiliates.

Security Vulnerability in Solaris SSH May Allow Unauthorized Access to X11 Sessions


Release Phase

Bug Id

Solaris 9 Operating System
Solaris 10 Operating System

Date of Workaround Release

Date of Resolved Release

A Security Vulnerability in Solaris SSH may allow Unauthorized Access to X11 Sessions

1. Impact

A security vulnerability related to X11 forwarding within the SSH product shipped with Solaris may allow a local unprivileged user to gain unauthorized access to another user's X11 session. This may allow execution of code with the privileges of that user or may result in the disclosure of sensitive data related to the user's session.

This issue is also referenced in the following document:

2. Contributing Factors

This issue can occur in the following releases:

SPARC Platform

  • Solaris 9 without patch 114356-14
  • Solaris 10 without patch 126133-03

x86 Platform

  • Solaris 9 without patch 114357-13
  • Solaris 10 without patch 126134-03
Note:  SSH is not shipped with Solaris 8 and therefore is not impacted by this issue.

This issue only affects systems which are configured to run the SSH service. The following can be used to determine if the sshd(1M) daemon is running on a host:
$ pgrep sshd || echo "sshd not running"
This issue only affects SSH sessions which have X11 forwarding enabled. By default users are allowed to enable this facility for any new sessions (see sshd(1)). To determine whether the X11 forwarding setting has been changed from the default, the sshd_config(4) file can
be examined, for example:
% grep X11Forwarding /etc/ssh/sshd_config
X11Forwarding no

3. Symptoms

There are no predictable symptoms that would indicate the described vulnerability has been exploited.

4. Workaround

To workaround this issue, X11 forwarding can be disabled for individual SSH sessions by running the ssh(1) as follows when those sessions are initiated:
$ ssh -o ForwardX11=no ...
$ ssh -x ...
Alternatively, the sshd_config(4) file on a host can be modified to disable X11 forwarding for all incoming SSH connections to that host, by changing the following line in "/etc/ssh/sshd_config" (or adding it if not already present) from:

X11Forwarding yes
X11Forwarding no
and then restarting ssh:

For Solaris 9:
# /etc/init.d/sshd stop ; /etc/init.d/sshd start
For Solaris 10:
# svcadm restart ssh

5. Resolution

This issue is addressed in the following releases:

SPARC Platform
  • Solaris 9 with patch 114356-14 or later
  • Solaris 10 with patch 126133-03 or later
x86 Platform
  • Solaris 9 with patch 114357-13 or later
  • Solaris 10 with patch 126134-03 or later
Note: The above patches have introduced a regression for systems that have only IPv4 interfaces configured. Please see Sun Alert 240906 for further information.

For more information on Security Sun Alerts, see 1009886.1.

This Sun Alert notification is being provided to you on an "AS IS" basis. This Sun Alert notification may contain information provided by third parties. The issues described in this Sun Alert notification may or may not impact your system(s). Sun makes no representations, warranties, or guarantees as to the information contained herein. ANY AND ALL WARRANTIES, EXPRESS OR IMPLIED, INCLUDING WITHOUT LIMITATION WARRANTIES OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE, OR NON-INFRINGEMENT, ARE HEREBY DISCLAIMED. BY ACCESSING THIS DOCUMENT YOU ACKNOWLEDGE THAT SUN SHALL IN NO EVENT BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, PUNITIVE, OR CONSEQUENTIAL DAMAGES THAT ARISE OUT OF YOUR USE OR FAILURE TO USE THE INFORMATION CONTAINED HEREIN. This Sun Alert notification contains Sun proprietary and confidential information. It is being provided to you pursuant to the provisions of your agreement to purchase services from Sun, or, if you do not have such an agreement, the Terms of Use. This Sun Alert notification may only be used for the purposes contemplated by these agreements.

Copyright 2000-2008 Sun Microsystems, Inc., 4150 Network Circle, Santa Clara, CA 95054 U.S.A. All rights reserved.

Modification History
23-May-2008: Updated Contributing Factors and Resolution sections
02-Jul-2008: Updated Contributing Factors and Resolution sections; now Resolved
20-Aug-2008: Updated Resolution section



This solution has no attachment