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                                    CERT-Renater

                         Note d'Information No. 2008/VULN163
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DATE                      : 07/05/2008

HARDWARE PLATFORM(S)      : /

OPERATING SYSTEM(S)       : Solaris 9, Solaris 10 running Solaris SSH.

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http://sunsolve.sun.com/search/printfriendly.do?assetkey=1-66-237444-1
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Solution Type: Sun Alert
    Solution  237444 :   Security Vulnerability in Solaris SSH May Allow
    Unauthorized Access to X11 Sessions
    Bug ID: 6684003

    Product
Solaris 9 Operating System, Solaris 10 Operating System

    Date of Workaround Release: 05-May-2008

    SA Document Body
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:

    CVE-2008-1483 at
    http://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2008-1483

2. Contributing Factors

    This issue can occur in the following releases:

    SPARC Platform
      * Solaris 9 Operating System
      * Solaris 10 Operating System

    x86 Platform
      * Solaris 9 Operating System
      * Solaris 10 Operating System

    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 ...

    OR

$ 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

    to

    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

    Interim Security Relief (ISR) is available from
    http://sunsolve.sun.com/tpatches for the following releases:
    SPARC Platform:
      * Solaris 9 IDR137882-03
      * Solaris 10 IDR137880-04

    x86 Platform:
      * Solaris 9 IDR137883-03
      * Solaris 10 IDR137881-04

    Note: This document refers to one or more Interim Security Relief
    (ISRs) which are designed to address the concerns identified herein.
    Sun has limited experience with these (ISRs) due to their interim
    nature. As such, you should only install the ISRs on systems meeting
    the configurations described above.  Sun may release full patches at a
    later date, however, Sun is under no obligation whatsoever to create,
    release, or distribute any such patch.

5. Resolution

    A final resolution is pending completion.
    For more information on Security Sun Alerts, see Technical
    Instruction ID 213557.
    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 Sun.com 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

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