SuSe: nfs-utils denial of service vulnerability

    Date15 Jul 2003
    CategorySuSE
    2842
    Posted ByLinuxSecurity Advisories
    There is an off-by-one bug in the xlog() function used by the rpc.mountd. It is possible for remote attackers to use this off-by-one overflow to execute arbitrary code as root.
    
    ______________________________________________________________________________
    
                            SuSE Security Announcement
    
            Package:                nfs-utils
            Announcement-ID:        SuSE-SA:2003:031
            Date:                   Tue Jul 15 14:00:00 MEST 2003
            Affected products:      7.2, 7.3, 8.0, 8.1, 8.2
                                    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
                                    SuSE Linux Desktop 1.0
            Vulnerability Type:     remote code execution
            Severity (1-10):        7
            SuSE default package:   yes
            Cross References:       CAN-2003-0252
                                     http://isec.pl/vulnerabilities/
    
        Content of this advisory:
            1) security vulnerability resolved: Off by one bug in rpc.mountd.
               problem description, discussion, solution and upgrade information
            2) pending vulnerabilities, solutions, workarounds:
                - xpdf/acroread
                - lbreakout
                - Eterm
                - gnats
                - unzip
            3) standard appendix (further information)
    
    ______________________________________________________________________________
    
    1)  problem description, brief discussion, solution, upgrade information
    
        The nfs-utils package contains various programs to offer and manage
        certain RPC services such as the rpc.mountd.
         iSEC Security Research has reported an off-by-one bug in the xlog()
        function used by the rpc.mountd. It is possible for remote attackers
        to use this off-by-one overflow to execute arbitrary code as root.
         Some of the products listed above seem not vulnerable to this
        one byte overflow due to the stack alignment generated by the compiler
        during the build. Nevertheless, since there is no easy workaround except
        shutting down the RPC services, an update is strongly recommended for
        every product listed above.
    
        This update needs to be applied to both NFS servers and clients,
        as the vulnerable function is used by mountd and statd.
    
        You can either restart these services manually, or use the
        corresponding init scripts:
    
          "rcnfsserver restart"           (for the NFS server)
          "rcnfs restart"                 (for the NFS client)
    
        Depending on your setup, it may be less disruptive to restart
        the two daemons manually.
    
        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-8.2:
         ftp://ftp.suse.com/pub/suse/i386/update/8.2/rpm/i586/nfs-utils-1.0.1-109.i586.rpm
          964386359a4280b0f64b5d06cc0debb4
        patch rpm(s):
         ftp://ftp.suse.com/pub/suse/i386/update/8.2/rpm/i586/nfs-utils-1.0.1-109.i586.patch.rpm
          5e67e844aa5d5c9d6fb3720f388813af
        source rpm(s):
         ftp://ftp.suse.com/pub/suse/i386/update/8.2/rpm/src/nfs-utils-1.0.1-109.src.rpm
          91695f1d03df64188c3a63126699a811
    
        SuSE-8.1:
         ftp://ftp.suse.com/pub/suse/i386/update/8.1/rpm/i586/nfs-utils-1.0.1-109.i586.rpm
          b212711af6445cb97773e30ed4284741
        patch rpm(s):
         ftp://ftp.suse.com/pub/suse/i386/update/8.1/rpm/i586/nfs-utils-1.0.1-109.i586.patch.rpm
          8b267ea76f715f64b8a041c2f24cee07
        source rpm(s):
         ftp://ftp.suse.com/pub/suse/i386/update/8.1/rpm/src/nfs-utils-1.0.1-109.src.rpm
          6da708a468ca48dd4078cbeff2c842f6
    
        SuSE-8.0:
         ftp://ftp.suse.com/pub/suse/i386/update/8.0/n1/nfs-utils-0.3.3-178.i386.rpm
          3cec45e5a7fdac0e9d6c67d894e90b16
        patch rpm(s):
         ftp://ftp.suse.com/pub/suse/i386/update/8.0/n1/nfs-utils-0.3.3-178.i386.patch.rpm
          5f86c33e9564e39df6f74c376d6d0ccd
        source rpm(s):
         ftp://ftp.suse.com/pub/suse/i386/update/8.0/zq1/nfs-utils-0.3.3-178.src.rpm
          f105acb95d3a770c4b142fd265bdf6a7
    
        SuSE-7.3:
         ftp://ftp.suse.com/pub/suse/i386/update/7.3/n1/nfs-utils-0.3.1-111.i386.rpm
          a4c43c562fc1d9ff65367795897d5fb5
        source rpm(s):
         ftp://ftp.suse.com/pub/suse/i386/update/7.3/zq1/nfs-utils-0.3.1-111.src.rpm
          dc56ab3deeb7a5ed6bde4e021ff35c10
    
        SuSE-7.2:
         ftp://ftp.suse.com/pub/suse/i386/update/7.2/n1/nfs-utils-0.3.1-112.i386.rpm
          1905a8a632eaf00dd5ad81f498ad6493
        source rpm(s):
         ftp://ftp.suse.com/pub/suse/i386/update/7.2/zq1/nfs-utils-0.3.1-112.src.rpm
          a048236b106c8a32bce936a39bdc0403
    
    
        Sparc Platform:
    
        SuSE-7.3:
         ftp://ftp.suse.com/pub/suse/sparc/update/7.3/n1/nfs-utils-0.3.1-49.sparc.rpm
          176b1636fa49520b3f700d399af39203
        source rpm(s):
         ftp://ftp.suse.com/pub/suse/sparc/update/7.3/zq1/nfs-utils-0.3.1-49.src.rpm
          2b3cd21df36acf2b6076993855ef179f
    
    
        PPC Power PC Platform:
    
        SuSE-7.3:
         ftp://ftp.suse.com/pub/suse/ppc/update/7.3/n1/nfs-utils-0.3.1-60.ppc.rpm
          0af7e6f702231a3194063a2c99473bb4
        source rpm(s):
         ftp://ftp.suse.com/pub/suse/ppc/update/7.3/zq1/nfs-utils-0.3.1-60.src.rpm
          6b4a8ea3c5e443d255e15123dc97b0e9
    
    ______________________________________________________________________________
    
    2)  Pending vulnerabilities in SuSE Distributions and Workarounds:
    
        - xpdf/acroread
        A problem regarding handling of external URLs by various
        PDF readers has been reported by CERT. Attackers could execute
        arbitrary commands as the user viewing the document by embedding
        shell meta characters in URLs.
          The xpdf PDF viewer as shipped with SuSE is not vulnerable to
        this attack due to its configuration. For the acrobat PDF reader
        we will provide updates on our ftp servers shortly.
    
        - lbreakout
        Various format string bugs in the code of the game lbreakout were
        reported for version 2-2.5. These bugs can be exploited remotely.
        SuSE Linux does not ship this vulnerable version of lbreakout.
    
        - Eterm
        A buffer overflow in eterm while handling the environment
        variable ETERMPATH can lead to local privilege escalation.
        SuSE do not ship eterm with higher privileges.
    
        - gnats
        Several security bugs were reported in gnats. These bugs will
        be fixed and update packages will released soon.
    
        - unzip
        Unzip can be tricked into overwriting files by using special
        zip archives. Fixed packages are available on our ftp servers.
    
    
    ______________________________________________________________________________
    
    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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