SuSE Linux Advisory: xf86

____________________________________________________________________________

                        SuSE Security Announcement

        Package:                xf86
        Announcement-ID:        SuSE-SA:2002:032
        Date:                   Wed Sep 18 12:00:00 MEST 2002
        Affecte products:       SuSE Linux 8.0
        Vulnerability Type:     local privilege escalation
        Severity (1-10):        5
        SuSE default package:   yes
        Cross References:       http://www.xfree.org/security

    Content of this advisory:
        1) security vulnerability resolved: LD_PRELOAD vulnerability in the X11
           library
           problem description, discussion, solution and upgrade information
        2) pending vulnerabilities, solutions, workarounds:
            - Perl 5.6.1 glob overflow fix
            - new OpenSSH packages
            - sparc info
        3) standard appendix (further information)

____________________________________________________________________________

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

    The xf86 package contains various libraries and programs which are
    fundamental for the X server to function.
      The libX11.so library from this package dynamically loads other libraries
    where the pathname is controlled by the user invoking the program linked
    against libX11.so. Unfortunately, libX11.so also behaves the same way when
    linked against setuid programs. This behavior allows local users to
    execute arbitrary code under a different UID which can be the root-UID in
    the worst case.
      libX11.so has been fixed to check for calls from setuid programs. It
    denies loading of user controlled libraries in this case.
      We recommend an update in any case since there is no easy workaround
    possible except removing the setuid bit from any program linked against
    libX11.so.

    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.

    i386 Intel Platform:

    SuSE-8.0
    ftp://ftp.suse.com/pub/suse/i386/update/8.0/x1/xshared-4.2.0-174.i386.rpm
      2a515055a811de5b465d016ffa77a09c
    ftp://ftp.suse.com/pub/suse/i386/update/8.0/x2/xdevel-4.2.0-174.i386.rpm
      67ddeb24b04b8c2badb7a039d9ea270e
    source rpm:
    ftp://ftp.suse.com/pub/suse/i386/update/8.0/zq1/xf86-4.2.0-174.src.rpm
      e44b3f6dd4a406bd422adc4f7fac63f2

____________________________________________________________________________

2)  Pending vulnerabilities in SuSE Distributions and Workarounds:

    - perl
    New Perl 5.6.1 packages will soon be available which fix overflows
    in the globbing code of the Perl interpreter. Although we believe
    that there is not much impact by this bug, we recommend an update
    especially on systems offering remote services based on Perl.

    - openssh
    New openssh packages are available for the SuSE Linux distributions
    7.0 - 7.3 (version 2.9.9p2). These packages have been rebuilt to
    contain the fixes in the openssl library, which is used by openssh.
    It is possible but not proven that the weaknesses in the openssl code
    (fixed and announced by SuSE-SA:2002:027) can be exploited in any way.
    We release the packages to prevent the possibility that the
    vulnerability exists. It is recommended to install the updates.

    - sparc
    Due to a lack of build power on the sparc architecture, we will
    discontinue providing security updates for the SuSE Linux 7.0 and 7.1
    distributions for sparc. We estimate that more than 95% of all SuSE
    Linux for sparc users use the most recent version 7.3 so that the loss
    should be considerably small.
    In addition to the update directories on ftp ftp.suse.com, we will also
    move the directories containing the distributions themselves into the
    discontinued/ tree on ftp.suse.com/pub/suse/discontinued/. By
    consequence, all updates will continue to be available, but the path
    indicates that these directories and files will remain there for
    archiving purposes only.
    Please note that mirrors of the SuSE ftp server ftp ftp.suse.com might not
    contain the discontinued/ directory tree.

____________________________________________________________________________

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.
       Prerequisites:
        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
    subscribe:

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

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

    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>