SuSe: sendmail buffer overflow vulnerability

    Date01 Apr 2003
    CategorySuSE
    2139
    Posted ByLinuxSecurity Advisories
    The nature of the flaw is a stack overflow in a function that is called frequently throughout the sendmail source code.
    
    ______________________________________________________________________________
    
                            SuSE Security Announcement
    
            Package:                sendmail, sendmail-tls
            Announcement-ID:        SuSE-SA:2003:023
            Date:                   Tuesday, April 1st 2003 18:45 MEST
            Affected products:      7.1, 7.2, 7.3, 8.0, 8.1, 8.2
                                    SuSE Linux Database Server,
                                    SuSE Linux Enterprise Server 7, 8
                                    SuSE Linux Firewall on CD/Admin host
                                    SuSE Linux Connectivity Server
                                    SuSE Linux Office Server
            Vulnerability Type:     local/remote privilege escalation
            Severity (1-10):        7
            SuSE default package:   yes (until SuSE Linux 8.0 and SLES7)
            Cross References:        http://www.cert.org/advisories/CA-2003-12.html
    
        Content of this advisory:
            1) security vulnerability resolved: sendmail, sendmail-tls
               problem description, discussion, solution and upgrade information
            2) pending vulnerabilities, solutions, workarounds:
                - glibc
                - vnc
                - openssl
            3) standard appendix (further information)
    
    ______________________________________________________________________________
    
    1)  problem description, brief discussion, solution, upgrade information
    
        sendmail is the most widely used mail transport agent (MTA) in the
        internet. A remotely exploitable buffer overflow has been found in all
        versions of sendmail that come with SuSE products. These versions include
        sendmail-8.11 and sendmail-8.12 releases. sendmail is the MTA subsystem
        that is installed by default on all SuSE products up to and including
        SuSE Linux 8.0 and the SuSE Linux Enterprise Server 7.
    
        The vulnerability was discovered by Michal Zalewski. It is not related
        to the vulnerability found by ISS in the first week of March as announced
        by SuSE Security in SuSE Security Announcement SuSE-SA:2003:013 (CERT
        Announcement ID CA-2003-07). The impact is believed to be a local root
        compromise with the possibility of a remote compromise. Even though
        the remote nature of the vulnerability is not confirmed, we believe that
        it is safe to assume that the vulnerability may be remotely exploitable.
        The nature of the flaw is a stack overflow in a function that is called
        frequently throughout the sendmail source code. The function is used for
        processing email addresses.
    
        There is no known workaround for this vulnerability other than using a
        different MTA. The vulnerability is triggered by an email message sent
        through the sendmail MTA subsystem. In that respect, it is different
        from commonly known bugs that occur in the context of an open TCP
        connection. By consequence, the vulnerability also exists if email
        messages get forwarded over a relay that itself does not run a vulnerable
        MTA. This specific detail and the wide distribution of sendmail in the
        internet causes this vulnerability to be considered a flaw of major
        severity. We recommend to install the update packages that are provided
        for download at the locations listed below.
    
        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.
    
        SPECIAL INSTALL INSTRUCTIONS:
        ==============================
        After performing the update, it is necessary to restart all running
        instances of sendmail using the command "rcsendmail restart" as root.
    
    
        Intel i386 Platform:
    
        SuSE-8.1:
         ftp://ftp.suse.com/pub/suse/i386/update/8.1/rpm/i586/sendmail-8.12.6-109.i586.rpm
          bb987c277374db2cf5ec81b7abe9a476
        patch rpm(s):
         ftp://ftp.suse.com/pub/suse/i386/update/8.1/rpm/i586/sendmail-8.12.6-109.i586.patch.rpm
          f90dc4e6f63b5c4e368e5db2fe7d09be
        source rpm(s):
         ftp://ftp.suse.com/pub/suse/i386/update/8.1/rpm/src/sendmail-8.12.6-109.src.rpm
          dd838b1089f6686a1107e6d8159b1f98
    
        SuSE-8.0:
         ftp://ftp.suse.com/pub/suse/i386/update/8.0/n1/sendmail-8.12.3-75.i386.rpm
          9e6949e973085ae3b628c52cadcc2c9e
        patch rpm(s):
         ftp://ftp.suse.com/pub/suse/i386/update/8.0/n1/sendmail-8.12.3-75.i386.patch.rpm
          dac55a8afcb2487b8b80549b9a4d7b38
        source rpm(s):
         ftp://ftp.suse.com/pub/suse/i386/update/8.0/zq1/sendmail-8.12.3-75.src.rpm
          f6e8297e885d367a73ff9010a6cbb297
    
        SuSE-7.3:
         ftp://ftp.suse.com/pub/suse/i386/update/7.3/n1/sendmail-8.11.6-164.i386.rpm
          7591a1d397e161225b4d594bcfc5bb02
         ftp://ftp.suse.com/pub/suse/i386/update/7.3/sec2/sendmail-tls-8.11.6-166.i386.rpm
          52c213438e8782af09a4395d402d1fea
        source rpm(s):
         ftp://ftp.suse.com/pub/suse/i386/update/7.3/zq1/sendmail-8.11.6-164.src.rpm
          a7b6f85673913089758f0ef0208aac6a
         ftp://ftp.suse.com/pub/suse/i386/update/7.3/zq1/sendmail-tls-8.11.6-166.src.rpm
          96cbfc4f2d85bdae71196ee80a4ebbd3
    
        SuSE-7.2:
         ftp://ftp.suse.com/pub/suse/i386/update/7.2/n1/sendmail-8.11.3-108.i386.rpm
          b107d5a44b234222de7e5fcb7998c192
         ftp://ftp.suse.com/pub/suse/i386/update/7.2/sec2/sendmail-tls-8.11.3-112.i386.rpm
          78a987bd0a38d067a8cffd6c6003abd8
        source rpm(s):
         ftp://ftp.suse.com/pub/suse/i386/update/7.2/zq1/sendmail-8.11.3-108.src.rpm
          0a86a2d3158110479c44c6b8a09f2bb6
         ftp://ftp.suse.com/pub/suse/i386/update/7.2/zq1/sendmail-tls-8.11.3-112.src.rpm
          acf234a4fa14d9d078df10cd774da0ce
    
        SuSE-7.1:
         ftp://ftp.suse.com/pub/suse/i386/update/7.1/n1/sendmail-8.11.2-45.i386.rpm
          abec9a5d08d89cabc662708b38cadfad
         ftp://ftp.suse.com/pub/suse/i386/update/7.1/sec2/sendmail-tls-8.11.2-47.i386.rpm
          36ab02484b69d9f6ac9d58b78cc0569d
        source rpm(s):
         ftp://ftp.suse.com/pub/suse/i386/update/7.1/zq1/sendmail-8.11.2-45.src.rpm
          e7e267fbb800277472f797f351796c6d
         ftp://ftp.suse.com/pub/suse/i386/update/7.1/zq1/sendmail-tls-8.11.2-47.src.rpm
          83b8fae134f192c53fa32c2d73f8dc8c
    
    
    
        Sparc Platform:
    
        SuSE-7.3:
         ftp://ftp.suse.com/pub/suse/sparc/update/7.3/n1/sendmail-8.11.6-65.sparc.rpm
          f3a9cff90e3ac9493bcab36b11dc692c
         ftp://ftp.suse.com/pub/suse/sparc/update/7.3/sec2/sendmail-tls-8.11.6-65.sparc.rpm
          63c14d646d8046df26c2899c0886bb24
        source rpm(s):
         ftp://ftp.suse.com/pub/suse/sparc/update/7.3/zq1/sendmail-8.11.6-65.src.rpm
          7f01e6aa454231f35f6ee50958bb6f29
         ftp://ftp.suse.com/pub/suse/sparc/update/7.3/zq1/sendmail-tls-8.11.6-65.src.rpm
          e9086795f386471e6b2476febb419aa0
    
    
    
    
        AXP Alpha Platform:
    
        SuSE-7.1:
        Limited package building resources are delaying the availiability of
        update packages for the SuSE Linux 7.1 for Alpha distribution.
    
    
        PPC Power PC Platform:
    
        SuSE-7.3:
         ftp://ftp.suse.com/pub/suse/ppc/update/7.3/n1/sendmail-8.11.6-123.ppc.rpm
          1dd1154f1b9ede1dc003be26919b4d23
         ftp://ftp.suse.com/pub/suse/ppc/update/7.3/sec2/sendmail-tls-8.11.6-122.ppc.rpm
          a83a7f0885deb049a5a63d8114e47af4
        source rpm(s):
         ftp://ftp.suse.com/pub/suse/ppc/update/7.3/zq1/sendmail-8.11.6-123.src.rpm
          2a199a60d825c8d3d2a1514fb58aea59
         ftp://ftp.suse.com/pub/suse/ppc/update/7.3/zq1/sendmail-tls-8.11.6-122.src.rpm
          621c390fbb8c44ffb1764d369c096d3f
    
        SuSE-7.1:
         ftp://ftp.suse.com/pub/suse/ppc/update/7.1/n1/sendmail-8.11.2-34.ppc.rpm
          c1657f4dbc2f4967fb3ca04c17e2f1f3
         ftp://ftp.suse.com/pub/suse/ppc/update/7.1/sec2/sendmail-tls-8.11.2-38.ppc.rpm
          7f564cc83d85970cd7c0f61896c916e6
        source rpm(s):
         ftp://ftp.suse.com/pub/suse/ppc/update/7.1/zq1/sendmail-8.11.2-34.src.rpm
          bd749453da2ff7513f09798d8b0b2e56
         ftp://ftp.suse.com/pub/suse/ppc/update/7.1/zq1/sendmail-tls-8.11.2-38.src.rpm
          1c347e9052b1b7dd02ae6630c56445db
    
    
    ______________________________________________________________________________
    
    2)  Pending vulnerabilities in SuSE Distributions and Workarounds:
    
        - glibc
          SuSE Security is working on glibc updates for the RPC XDR integer overflow
          security problem in glibc. The central function of the glibc package in a
          Linux system requires extensive testing of the update packages. The update
          packages will be provided for download at the usual location and
          publically announced as soon as the testing is completed successfully.
    
        - 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.
    
        - openssl
          A paper regarding remote timing attacks against OpenSSL has been
          published by researchers of the Stanford University. It is possible
          to extract the private RSA key used by services using OpenSSL by
          observing their timing behavior. Fixed packages will be available
          on our FTP servers 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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