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                                  CERT-Renater

                       Note d'Information No. 2005/VULN411
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DATE                      : 27/06/2005

HARDWARE PLATFORM(S)      : /

OPERATING SYSTEM(S)       : Systems running Samba.

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Sun(sm) Alert Notification
      * Sun Alert ID: 101783
      * Synopsis: Security Vulnerability in Samba's "ms_fnmatch()"
        Function May Result in a Denial of Service (DoS)
      * Category: Security
      * Product: Solaris 9 Operating System, Solaris 10 Operating System
      * BugIDs: 6218964
      * Avoidance: Patch, Workaround
      * State: Workaround
      * Date Released: 23-Jun-2005
      * Date Closed:
      * Date Modified:

1. Impact

    A security vulnerability in Samba's "ms_fnmatch()" function may allow
    a remote unprivileged user the ability to create a Denial of Service
    (DoS) by causing excessive CPU consumption via a Samba request that
    contains multiple wildcard characters.

    This issue is referenced in the following document:
      * CAN-2004-0930 at:
        http://www.cve.mitre.org/cgi-bin/cvename.cgi?name=CAN-2004-0930

2. Contributing Factors

    This issue can occur in the following releases:

    SPARC Platform
      * Solaris 9
      * Solaris 10 without patch 119757-01

    x86 Platform
      * Solaris 9
      * Solaris 10 without patch 119758-01

    Note: Solaris 7 and Solaris 8 do not include the Samba software and
    are not affected by this issue.

    The described issue only occurs if both of the following conditions
    are true:
     1. The system is configured as a Samba server.
     2. The version of Samba installed is 2.x through 3.0.7

    To determine if a system is configured as a Samba server, use the
    following command to check for the presence of the smb.conf(4) file:
     % ls -l /etc/sfw/smb.conf
     -rw-r--r-- 1 root other 11665 Sep 28 16:37 /etc/sfw/smb.conf

    If the output is similar to that shown above, the system is configured
    as a Samba server.

    To determine the version of Samba installed on a system, the following
    command can be run:
     % /usr/sfw/sbin/smbd -V
     Version 3.0


3. Symptoms

    If the described issue occurs, the Samba server running on an impacted
    machine will consume more CPU cycles than normal, reducing the quality
    of service provided by the Samba server. In some circumstances the
    server may become entirely unresponsive.

4. Relief/Workaround

    The Samba Server Security web page:
     http://www.samba.org/samba/docs/server_security.html

    documents several ways to restrict access to Samba servers and further
    protect Samba servers. Sites may consider applying the advice there
    even for patched systems.

    Until patches are available or can be applied, sites may consider
    downloading and compiling Samba 3.0.8 or higher from the Samba site
    at:
     http://www.samba.org

    as an interim workaround. Note however that the downloaded Samba
    software is not supported by Sun.

5. Resolution

    This issue is addressed in the following releases:

    SPARC Platform
      * Solaris 10 with patch 119757-01 or later

    x86 Platform
      * Solaris 10 with patch 119758-01 or later

    A final resolution is pending completion.

    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 2000-2005 Sun Microsystems, Inc., 4150 Network Circle, Santa
    Clara, CA 95054 U.S.A. All rights reserved

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