SuSe: openssl information leak

    Date27 Feb 2003
    CategorySuSE
    1982
    Posted ByLinuxSecurity Advisories
    A security weakness has been found, known as "Vaudenay timing attack on CBC"
    
    ______________________________________________________________________________
    
                            SuSE Security Announcement
    
            Package:                openssl
            Announcement-ID:        SuSE-SA:2003:011
            Date:                   Wednesday, Feb. 26th 2003 15:20 MET
            Affected products:      7.1, 7.2, 7.3, 8.0, 8.1
                                    SuSE Linux Database Server,
                                    SuSE eMail Server III, 3.1
                                    SuSE Linux Enterprise Server 7
                                    SuSE Linux Enterprise Server 8
                                    SuSE Linux Firewall on CD/Admin host
                                    SuSE Linux Connectivity Server
                                    SuSE Linux Office Server
            Vulnerability Type:     remote attack on encryption
            Severity (1-10):        5
            SuSE default package:   yes
            Cross References:       CAN-2003-0078
    
        Content of this advisory:
            1) security vulnerability resolved: openssl
               problem description, discussion, solution and upgrade information
            2) pending vulnerabilities, solutions, workarounds:
                - vnc
                - w3m
            3) standard appendix (further information)
    
    ______________________________________________________________________________
    
    1)  problem description, brief discussion, solution, upgrade information
    
        OpenSSL is an implementation of the Secure Sockets Layer and Transport
        Layer Security protocols and provides strong cryptography for many
        applications in a Linux system. It is a default package in all SuSE
        products.
    
        A security weakness has been found, known as "Vaudenay timing attack
        on CBC", named after one of the discoverers (Brice Canvel (EPFL), Alain
        Hiltgen (UBS), Serge Vaudenay (EPFL), and Martin Vuagnoux (EPFL, Ilion)).
        The weakness may allow an attacker to obtain a plaintext data block by
        observing timing differences in response to two different error cases
        (cipher padding errors vs. MAC verification errors).
        In order to exploit this vulnerability, the attacker has to meet certain
        requirements: The network connection between client and server must be
        of high quality to be able to observe timing differences, the attacker
        must be able to perform a man-in-the-middle attack, the transactions
        must repeatedly contain the same (encrypted) plain text block (such as
        a pop password or alike), and decoding failures in the SSL layer must
        not be propagated to the application that is using the SSL connection.
        These exploitation conditions considerably reduce the security risk
        imposed by the vulnerability. However, we recommend to completely
        remedy this weakness by installing the update packages for your system
        according to the following guidelines. There does not exist any temporary
        workaround for this problem other than applying the update packages.
    
    
        Please download the update package for your distribution and verify its
        integrity by the methods listed in section 3) of this announcement.
        Our maintenance customers are being notified individually. The packages
        are being offered to install from the maintenance web.
    
        SPECIAL INSTALLATION INSTRUCTIONS:
        ====================================
        Please update your openssl package using the command
            rpm -Fhv 
        The operation of this command must not be interrupted! An interrupted
        update of the openssl package may cause large protions of your system to
        fail.
        After performing the update, it is adviseable to run the command
        "ldconfig" to update the shared library loading cache.
        After the update, running processes in your system will continue to
        use the shared libraries from the old package before the update.
        Generally, it is necessary to restart all of these processes to
        completely fix the vulnerability in your system. The command
            lsof -n 2>/dev/null | grep RPMDELETE
        can be used to find the binaries and processes that still use the old
        shared libraries. In all cases, the next reboot of the system will cause
        the old shared libraries to be completely removed from the system.
        Alternatively, a transition to runlevel 1 (single user mode) and back
        to the default runlevel will have the same effect.
    
    
    
        Intel i386 Platform:
    
        SuSE-8.1:
         ftp://ftp.suse.com/pub/suse/i386/update/8.1/rpm/i586/openssl-0.9.6g-55.i586.rpm
          7fbf4d975180a20ff8dedc8adbdecc59
        patch rpm(s):
         ftp://ftp.suse.com/pub/suse/i386/update/8.1/rpm/i586/openssl-0.9.6g-55.i586.patch.rpm
          6ed4321ec536aa718189702470c33091
        source rpm(s):
         ftp://ftp.suse.com/pub/suse/i386/update/8.1/rpm/src/openssl-0.9.6g-55.src.rpm
          90fc753346dd2aff00eee4c530cea84a
    
        SuSE-8.0:
         ftp://ftp.suse.com/pub/suse/i386/update/8.0/sec1/openssl-0.9.6c-83.i386.rpm
          d6246b820780993cc0e2b48597743a8f
        patch rpm(s):
         ftp://ftp.suse.com/pub/suse/i386/update/8.0/sec1/openssl-0.9.6c-83.i386.patch.rpm
          2d933e913a9062de6a1fa35de969d211
        source rpm(s):
         ftp://ftp.suse.com/pub/suse/i386/update/8.0/zq1/openssl-0.9.6c-83.src.rpm
          b4b887a7311e9734a14d11e1a380f76e
    
        SuSE-7.3:
         ftp://ftp.suse.com/pub/suse/i386/update/7.3/sec1/openssl-0.9.6b-154.i386.rpm
          d3c0f892441c09c8c5a689e2af04ba55
        source rpm(s):
         ftp://ftp.suse.com/pub/suse/i386/update/7.3/zq1/openssl-0.9.6b-154.src.rpm
          31ec962fe3549a713b9e6937190a88fb
    
        SuSE-7.2:
         ftp://ftp.suse.com/pub/suse/i386/update/7.2/sec1/openssl-0.9.6a-78.i386.rpm
          d14f67c34c589f168b750b18c9162508
        source rpm(s):
         ftp://ftp.suse.com/pub/suse/i386/update/7.2/zq1/openssl-0.9.6a-78.src.rpm
          2ba5a416d6ca3cb75c9aabb5a25bb532
    
        SuSE-7.1:
         ftp://ftp.suse.com/pub/suse/i386/update/7.1/sec1/openssl-0.9.6a-78.i386.rpm
          c6b711573555982fadd31cfa179dd9dc
        source rpm(s):
         ftp://ftp.suse.com/pub/suse/i386/update/7.1/zq1/openssl-0.9.6a-78.src.rpm
          d00df30aa6ec6a3872c58da709181879
    
    
    
        Sparc Platform:
    
        SuSE-7.3:
         ftp://ftp.suse.com/pub/suse/sparc/update/7.3/sec1/openssl-0.9.6b-87.sparc.rpm
          6a8f19a49a698b93e740121321f59e5d
        source rpm(s):
         ftp://ftp.suse.com/pub/suse/sparc/update/7.3/zq1/openssl-0.9.6b-87.src.rpm
          50712c3fd35042278063622ad5cc77c7
    
        AXP Alpha Platform:
        The packages for the 7.1-axp distribution will be published soon.
    
    
    
        PPC Power PC Platform:
    
        SuSE-7.3:
         ftp://ftp.suse.com/pub/suse/ppc/update/7.3/sec1/openssl-0.9.6b-147.ppc.rpm
          051ef85d8e711819b2de38f55dc0023a
        source rpm(s):
         ftp://ftp.suse.com/pub/suse/ppc/update/7.3/zq1/openssl-0.9.6b-147.src.rpm
          58631776b8fa88932eb57069a7f2878e
    
        SuSE-7.1:
         ftp://ftp.suse.com/pub/suse/ppc/update/7.1/sec1/openssl-0.9.6a-28.ppc.rpm
          da5e7caa177316f3016dd98497e580de
        source rpm(s):
         ftp://ftp.suse.com/pub/suse/ppc/update/7.1/zq1/openssl-0.9.6a-28.src.rpm
          b317144556c8f1890d15f304d95c5764
    
    
    
    ______________________________________________________________________________
    
    2)  Pending vulnerabilities in SuSE Distributions and Workarounds:
    
      - vnc
        VNC (Virtual Network Computing) uses a weak cookie generation process
        which can be exploited by an attacker to bypass authentication.
        New packages are currently being tested and will be available on our
        FTP servers soon.
    
      - w3m
        The textbased web-browser w3m does not properly escape HTML tags.
        A malicious HTML page or img alt attribute may lead to information
        leakage. New packages will be available soon.
    ______________________________________________________________________________
    
    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 
           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 This email address is being protected from spambots. You need JavaScript enabled to view it.),
           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 
           to verify the signature of the package, where  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 "This email address is being protected from spambots. You need JavaScript enabled to view it." 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:
    
        This email address is being protected from spambots. You need JavaScript enabled to view it.
            -   general/linux/SuSE security discussion.
                All SuSE security announcements are sent to this list.
                To subscribe, send an email to
                    <This email address is being protected from spambots. You need JavaScript enabled to view it.>.
    
        This email address is being protected from spambots. You need JavaScript enabled to view it.
            -   SuSE's announce-only mailing list.
                Only SuSE's security announcements are sent to this list.
                To subscribe, send an email to
                    <This email address is being protected from spambots. You need JavaScript enabled to view it.>.
    
        For general information or the frequently asked questions (faq)
        send mail to:
            <This email address is being protected from spambots. You need JavaScript enabled to view it.> or
            <This email address is being protected from spambots. You need JavaScript enabled to view it.> respectively.
    
        =====================================================================
        SuSE's security contact is <This email address is being protected from spambots. You need JavaScript enabled to view it.> or <This email address is being protected from spambots. You need JavaScript enabled to view it.>.
        The <This email address is being protected from spambots. You need JavaScript enabled to view it.> 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 <This email address is being protected from spambots. You need JavaScript enabled to view it.>
    pub  1024D/9C800ACA 2000-10-19 SuSE Package Signing Key <This email address is being protected from spambots. You need JavaScript enabled to view it.>
    
    
    
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