SuSE Linux Advisory: samba


                        SuSE Security Announcement

        Package:                samba
        Announcement-ID:        SuSE-SA:2002:045
        Date:                   Wednesday, November 20th 2002 16:00 MET
        Affected products:      7.2, 7.3, 8.0, 8.1
                                SuSE Linux Database Server,
                                SuSE eMail Server III, 3.1
                                SuSE Linux Enterprise Server 7+8,
                                SuSE Linux Firewall on CD/Admin host
                                SuSE Linux Connectivity Server
                                SuSE Linux Office Server
        Vulnerability Type:     possible remote code execution
        Severity (1-10):        7
        SuSE default package:   no
        Cross References:       http://www.samba.org/

    Content of this advisory:
        1) security vulnerability resolved: samba
           problem description, discussion, solution and upgrade information
        2) pending vulnerabilities, solutions, workarounds
        3) standard appendix (further information)


1)  problem description, brief discussion, solution, upgrade information

    Samba developer Steve Langasek found a security problem in samba, the
    widely known free implementation of the SMB protocol.

    The error consists of a buffer overflow in a commonly used routine
    that accepts user input and may write up to 127 bytes past the end of
    the buffer allocated with static length, leaving enough room for
    an exploit. The resulting vulnerability can be exploited locally
    in applications using the pam_smbpass Pluggable Authentication Module
    (PAM). It may be possible to exploit this vulnerability remotely,
    causing the running smbd to crash or even to execute arbitrary code.

    The samba package is installed by default only on the SuSE Linux
    Enterprise Server. SuSE Linux products do not have the samba and
    samba-client packages installed by default.
    The samba packages in SuSE Linux version 7.1 and before are not affected
    by this vulnerability.
    For the bug to be exploited, your system has to be running the smbd
    samba server, or an administrator must have (manually) changed the
    configuration of the PAM authentification subsystem to enable the use
    of the pam_smbpass module. The samba server process(es) are not activated
    automatically after installation (of the package).

    The samba subsystem on SuSE products is split into two different
    subpackages: samba and smbclnt up to and including SuSE Linux 7.2, on
    SuSE Linux 7.3 and newer the package names are samba and samba-client.
    To completely remove the vulnerability, you should update all of the
    installed packages.

    We wish to express our gratitude to the samba development team and
    in particular to Steve Langasek and Volker Lendecke who provided the
    patches and communicated them to the vendors. Please know that the
    samba team will release the new version 2.2.7 of the samba software to
    address the security fix at the same time as this announcement gets
    published. More information about samba (and the security fix) is
    available at http://www.samba.org.

    Please download the update package for your distribution and verify its
    integrity by the methods listed in section 3) of this announcement.
    Then, install the package using the command "rpm -Fhv file.rpm" to apply
    the update.
    Our maintenance customers are being notified individually. The packages
    are being offered to install from the maintenance web.

    After successfully installing the update packages, you should restart
    the samba server process(es) to make the changes in the system effective.
    If you do not have a samba server running on your system, no further
    action is required. If you have a samba server running, please run the
    following command as root:
        rcsmb restart      # SuSE Linux, all versions
        rcnmb restart      # only on SuSE Linux 8.1

    Intel i386 Platform:

    patch rpm(s):
    source rpm(s):

    patch rpm(s):
    source rpm(s):

    source rpm(s):

    source rpm(s):

    Sparc Platform:

    source rpm(s):

    PPC Power PC Platform:

    source rpm(s):


2)  Pending vulnerabilities in SuSE Distributions and Workarounds:

  - 7.0 update trees
    We will move the SuSE Linux 7.0 update tree structure to the
    /pub/suse/discontinued/ tree shortly, following the announcement about
    discontinued products on Tue, 29 Oct 2002.


3)  standard appendix: authenticity verification, additional information

  - Package authenticity verification:

    SuSE update packages are available on many mirror ftp servers all over
    the world. While this service is being considered valuable and important
    to the free and open source software community, many users wish to be
    sure about the origin of the package and its content before installing
    the package. There are two verification methods that can be used
    independently from each other to prove the authenticity of a downloaded
    file or rpm package:
    1) md5sums as provided in the (cryptographically signed) announcement.
    2) using the internal gpg signatures of the rpm package.

    1) execute the command
        md5sum <name-of-the-file.rpm>
       after you downloaded the file from a SuSE ftp server or its mirrors.
       Then, compare the resulting md5sum with the one that is listed in the
       announcement. Since the announcement containing the checksums is
       cryptographically signed (usually using the key security@suse.de),
       the checksums show proof of the authenticity of the package.
       We disrecommend to subscribe to security lists which cause the
       email message containing the announcement to be modified so that
       the signature does not match after transport through the mailing
       list software.
       Downsides: You must be able to verify the authenticity of the
       announcement in the first place. If RPM packages are being rebuilt
       and a new version of a package is published on the ftp server, all
       md5 sums for the files are useless.

    2) rpm package signatures provide an easy way to verify the authenticity
       of an rpm package. Use the command
        rpm -v --checksig <file.rpm>
       to verify the signature of the package, where <file.rpm> is the
       filename of the rpm package that you have downloaded. Of course,
       package authenticity verification can only target an un-installed rpm
       package file.
        a) gpg is installed
        b) The package is signed using a certain key. The public part of this
           key must be installed by the gpg program in the directory
           ~/.gnupg/ under the user's home directory who performs the
           signature verification (usually root). You can import the key
           that is used by SuSE in rpm packages for SuSE Linux by saving
           this announcement to a file ("announcement.txt") and
           running the command (do "su -" to be root):
            gpg --batch; gpg < announcement.txt | gpg --import
           SuSE Linux distributions version 7.1 and thereafter install the
           key "build@suse.de" upon installation or upgrade, provided that
           the package gpg is installed. The file containing the public key
           is placed at the top-level directory of the first CD (pubring.gpg)
           and at ftp://ftp.suse.com/pub/suse/pubring.gpg-build.suse.de .

  - SuSE runs two security mailing lists to which any interested party may

        -   general/linux/SuSE security discussion.
            All SuSE security announcements are sent to this list.
            To subscribe, send an email to

        -   SuSE's announce-only mailing list.
            Only SuSE's security announcements are sent to this list.
            To subscribe, send an email to

    For general information or the frequently asked questions (faq)
    send mail to:
        <suse-security-info@suse.com> or
        <suse-security-faq@suse.com> respectively.

    SuSE's security contact is <security@suse.com> or <security@suse.de>.
    The <security@suse.de> public key is listed below.

    The information in this advisory may be distributed or reproduced,
    provided that the advisory is not modified in any way. In particular,
    it is desired that the clear-text signature shows proof of the
    authenticity of the text.
    SuSE Linux AG makes no warranties of any kind whatsoever with respect
    to the information contained in this security advisory.

Type Bits/KeyID    Date       User ID
pub  2048R/3D25D3D9 1999-03-06 SuSE Security Team <security@suse.de>
pub  1024D/9C800ACA 2000-10-19 SuSE Package Signing Key <build@suse.de>

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