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UNIRAS Brief - 587/04 - SUSE Security Announcement



 
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   UNIRAS (UK Govt CERT) Briefing Notice - 587/04 dated 22.10.04  Time: 14:55  
  UNIRAS is part of NISCC (National Infrastructure Security Co-ordination Centre)
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  UNIRAS material is also available from its website at www.uniras.gov.uk and
         Information about NISCC is available from www.niscc.gov.uk
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Title
=====

SUSE Security Announcement - kernel

Detail
====== 

An integer underflow problem in the iptables firewall logging rules
can allow a remote attacker to crash the machine by using a handcrafted
IP packet. This attack is only possible with firewalling enabled.
______________________________________________________________________________

                        SUSE Security Announcement

        Package:                kernel
        Announcement-ID:        SUSE-SA:2004:037
        Date:                   Wednesday, Oct 20th 2004 18:00 MEST
        Affected products:      9.1
                                SUSE Linux Enterprise Server 9
        Vulnerability Type:     remote denial of service
        Severity (1-10):        9
        SUSE default package:   yes
        Cross References:       CAN-2004-0816
                                CAN-2004-0887

    Content of this advisory:
        1) security vulnerability resolved:
             - remote system crash with enabled firewall
             - local root exploit on the S/390 platform
             - minor /proc information leaks
           problem description
        2) solution/workaround
        3) special instructions and notes
        4) package location and checksums
        5) pending vulnerabilities, solutions, workarounds:
            - libtiff
            - cyrus-sasl
            - php4
            - zinf

______________________________________________________________________________

1) problem description, brief discussion

   An integer underflow problem in the iptables firewall logging rules
   can allow a remote attacker to crash the machine by using a handcrafted
   IP packet. This attack is only possible with firewalling enabled.

   We would like to thank Richard Hart for reporting the problem.

   This problem has already been fixed in the 2.6.8 upstream Linux kernel,
   this update contains a backport of the fix.

   Products running a 2.4 kernel are not affected.

   Mitre has assigned the CVE ID CAN-2004-0816 for this problem.


   Additionaly Martin Schwidefsky of IBM found an incorrectly handled
   privileged instruction which can lead to a local user gaining
   root user privileges.

   This only affects the SUSE Linux Enterprise Server 9 on the S/390
   platform and has been assigned CVE ID CAN-2004-0887.


   Additionaly the following non-security bugs were fixed:

   - Two CD burning problems.

   - USB 2.0 stability problems under high load on SMP systems.

   - Several SUSE Linux Enterprise Server issues.
     (see the Maintenance Information Mail for more informations).


2) solution/workaround

   If you are not using an iptables based firewall (like SUSEfirewall2)
   on your system, you are not affected.

   If you are using a firewall, a workaround is to disable firewall
   logging of IP and TCP options.

   We recommend to update the kernel.

3) special instructions and notes

    SPECIAL INSTALL INSTRUCTIONS:
    ==============================
    The following paragraphs will guide you through the installation
    process in a step-by-step fashion. The character sequence "****"
    marks the beginning of a new paragraph. In some cases, the steps
    outlined in a particular paragraph may or may not be applicable
    to your situation.
    Therefore, please make sure to read through all of the steps below
    before attempting any of these procedures.
    All of the commands that need to be executed are required to be
    run as the superuser (root). Each step relies on the steps before
    it to complete successfully.


  **** Step 1: Determine the needed kernel type

    Please use the following command to find the kernel type that is
    installed on your system:

      rpm -qf /boot/vmlinuz

    Following are the possible kernel types (disregard the version and
    build number following the name separated by the "-" character)

      kernel-64k-pagesize
      kernel-bigsmp
      kernel-default
      kernel-smp

  **** Step 2: Download the package for your system

    Please download the kernel RPM package for your distribution with the
    name as indicated by Step 1. The list of all kernel rpm packages is
    appended below. Note: The kernel-source package does not
    contain a binary kernel in bootable form. Instead, it contains the
    sources that the binary kernel rpm packages are created from. It can be
    used by administrators who have decided to build their own kernel.
    Since the kernel-source.rpm is an installable (compiled) package that
    contains sources for the linux kernel, it is not the source RPM for
    the kernel RPM binary packages.

    The kernel RPM binary packages for the distributions can be found at the
    locations below ftp://ftp.suse.com/pub/suse/i386/update/.

      9.1/rpm/i586

    After downloading the kernel RPM package for your system, you should
    verify the authenticity of the kernel rpm package using the methods as
    listed in section 3) of each SUSE Security Announcement.


  **** Step 3: Installing your kernel rpm package

    Install the rpm package that you have downloaded in Steps 3 or 4 with
    the command
        rpm -Uhv --nodeps --force <K_FILE.RPM>
    where <K_FILE.RPM> is the name of the rpm package that you downloaded.

    Warning: After performing this step, your system will likely not be
             able to boot if the following steps have not been fully
             followed.


  **** Step 4: configuring and creating the initrd

    The initrd is a ramdisk that is loaded into the memory of your
    system together with the kernel boot image by the bootloader. The
    kernel uses the content of this ramdisk to execute commands that must
    be run before the kernel can mount its actual root filesystem. It is
    usually used to initialize SCSI drivers or NIC drivers for diskless
    operation.

    The variable INITRD_MODULES in /etc/sysconfig/kernel determines
    which kernel modules will be loaded in the initrd before the kernel
    has mounted its actual root filesystem. The variable should contain
    your SCSI adapter (if any) or filesystem driver modules.

    With the installation of the new kernel, the initrd has to be
    re-packed with the update kernel modules. Please run the command

      mk_initrd

    as root to create a new init ramdisk (initrd) for your system.
    On SuSE Linux 8.1 and later, this is done automatically when the
    RPM is installed.


  **** Step 5: bootloader

    If you run a SUSE LINUX 8.x, SLES8, or SUSE LINUX 9.x system, there
    are two options:
    Depending on your software configuration, you have either the lilo
    bootloader or the grub bootloader installed and initialized on your
    system.
    The grub bootloader does not require any further actions to be
    performed after the new kernel images have been moved in place by the
    rpm Update command.
    If you have a lilo bootloader installed and initialized, then the lilo
    program must be run as root. Use the command

      grep LOADER_TYPE /etc/sysconfig/bootloader

    to find out which boot loader is configured. If it is lilo, then you
    must run the lilo command as root. If grub is listed, then your system
    does not require any bootloader initialization.

    Warning: An improperly installed bootloader may render your system
             unbootable.

  **** Step 6: reboot

    If all of the steps above have been successfully completed on your
    system, then the new kernel including the kernel modules and the
    initrd should be ready to boot. The system needs to be rebooted for
    the changes to become active. Please make sure that all steps have
    completed, then reboot using the command
        shutdown -r now
    or
        init 6

    Your system should now shut down and reboot with the new kernel.


4) package location and checksums

    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.


    x86 Platform:

    SUSE Linux 9.1:
    ftp://ftp.suse.com/pub/suse/i386/update/9.1/rpm/i586/kernel-default-2.6.5-7.111.i586.rpm
      735f99730442772d0caeb1043576da0e
    ftp://ftp.suse.com/pub/suse/i386/update/9.1/rpm/i586/kernel-smp-2.6.5-7.111.i586.rpm
      8e38495a90203fdeef0167126e9699fd
    ftp://ftp.suse.com/pub/suse/i386/update/9.1/rpm/i586/kernel-bigsmp-2.6.5-7.111.i586.rpm
      54474a313ff90c5a5ded8cd3590016ee
    source rpm(s):
    ftp://ftp.suse.com/pub/suse/i386/update/9.1/rpm/src/kernel-default-2.6.5-7.111.nosrc.rpm
      60a46f48bbae6989a50d2b3c735cd176
    ftp://ftp.suse.com/pub/suse/i386/update/9.1/rpm/src/kernel-smp-2.6.5-7.111.nosrc.rpm
      5bc77692dc82521b83378c97d39acd72
    ftp://ftp.suse.com/pub/suse/i386/update/9.1/rpm/src/kernel-bigsmp-2.6.5-7.111.nosrc.rpm
      348c5d63b8c26c548d8b5bfcc894b805


    x86-64 Platform:

    SUSE Linux 9.1:
    ftp://ftp.suse.com/pub/suse/x86_64/update/9.1/rpm/x86_64/kernel-default-2.6.5-7.111.x86_64.rpm
      53ec1285f8933f79b6e53f2cb4d2094a
    ftp://ftp.suse.com/pub/suse/x86_64/update/9.1/rpm/x86_64/kernel-smp-2.6.5-7.111.x86_64.rpm
      de3bf18c94d26a2b3477cf11cf723380
    source rpm(s):
    ftp://ftp.suse.com/pub/suse/x86_64/update/9.1/rpm/src/kernel-default-2.6.5-7.111.nosrc.rpm
      3e6123bd50f2802cf6a96ccfa2af674f
    ftp://ftp.suse.com/pub/suse/x86_64/update/9.1/rpm/src/kernel-smp-2.6.5-7.111.nosrc.rpm
      365354d9e91032e53436f949da6ae8f6

______________________________________________________________________________

5)  Pending vulnerabilities in SUSE Distributions and Workarounds:

    libtiff
        - Several buffer and integer overflows have been found in the
          image handling library libtiff by Chris Evans and Dmitry Levin,
          recorded under CVE Ids: CAN-2004-0803,CAN-2004-0804,CAN-2004-0886.

          We are working on updates and will release them within the
          next days.

    cyrus-sasl
        - The SASL_PATH environment variable was also used to load
          plugins even with setuid privileges set, which can lead to a
          local root privilege escalation.

          The default SUSE installation was not found to be affected
          by this problem, neithertheless we are in the process of
          releasing updates. The CVE ID for this issue is: CAN-2004-0884

    php4
        - File overwrite problems were identified in php4. We have
          released updates for this issue.
          However, due to problems with php4-recode in combination with
          php4-mysql we had to withdraw the update from YaST2
          Online Update for some SUSE Linux versions.
          New packages will be available soon.

    zinf
        - A tempfile race condition in zinf / freeamp was fixed, packages
          are available.

    phpMyAdmin
        - A bug in phpMyAdmin that would allow users to execute
          arbitrary commands has been discovered. New packages will be
          available soon.

    mysql
        - Several bugs in mysql have been discovered. New packages
          will be available soon.

    libpng
        - The issues with libpng described in CAN-2004-0954 and
          CAN-2004-0955 where already fixed in the last libpng update.
          Fixed packages are therefore already available on our ftp
          server.

______________________________________________________________________________

6)  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@xxxxxxx),
       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@xxxxxxx" 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@xxxxxxxx
        -   general/linux/SUSE security discussion.
            All SUSE security announcements are sent to this list.
            To subscribe, send an email to
                <suse-security-subscribe@xxxxxxxx>.

    suse-security-announce@xxxxxxxx
        -   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@xxxxxxxx>.

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

    =====================================================================
    SUSE's security contact is <security@xxxxxxxx> or <security@xxxxxxx>.
    The <security@xxxxxxx> 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@xxxxxxx> pub  1024D/9C800ACA 2000-10-19 SuSE Package Signing Key <build@xxxxxxx>


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UNIRAS wishes to acknowledge the contributions of Suse for the information 
contained in this Briefing. 
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This Briefing contains the information released by the original author. Some 
of the information may have changed since it was released. If the vulnerability 
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<End of UNIRAS Briefing>

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