SuSE alert: samba

Posted by dave on Jun 29, 2001 4:56 AM EDT
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Michal Zalewski discovered that a remote attacker can write to files owned by root if the samba config file /etc/smb.conf contains the %m macro to specify the logfile for logging access to the samba server. The %m macro substitutes the NetBIOS name - improper validation of this name allows an attacker to write to any file in the system.



                        SuSE Security Announcement

        Package: samba
        Announcement-ID: SuSE-SA:2001:021
        Date: Friday, Jun 29th 2001 14:45 MEST
        Affected SuSE versions: (6.0, 6.1, 6.2) 6.3, 6.4, 7.0, 7.1, 7.2
        Vulnerability Type: possible remote root compromise
        Severity (1-10): 7
        SuSE default package: yes
        Other affected systems: systems using samba and the %m macro in the
                                samba main config file

    Content of this advisory:
        1) security vulnerability resolved: samba
           problem description, discussion, solution and upgrade information
        2) pending vulnerabilities, solutions, workarounds
        3) standard appendix (further information)


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

    Michal Zalewski discovered that a remote attacker can write to files
    owned by root if the samba config file /etc/smb.conf contains the %m
    macro to specify the logfile for logging access to the samba server.
    The %m macro substitutes the NetBIOS name - improper validation of
    this name allows an attacker to write to any file in the system.

    SuSE Linux distributions do not ship a default /etc/smb.conf config
    file that contains the %m macro. Therefore, SuSE distributions are not
    vulnerable to the bug in the out-of-the-box state.

    In addition to the remotely exploitable bug, there exists another
    vulnerability which is fixed with the update packages we provide
    below: temporary files are being handled insecurely so that an
    attacker with local access to the system can increase her privileges.
    This error was discovered by Marcus Meissner, Caldera. This specific
    problem has been fixed with the release of the samba-2.0.9 version.
    samba release version 2.0.8 intended to correct this local problem, but
    due to an error, 2.0.9 contained the complete fix.

    Only the 2.0.10 version as offered for the SuSE Linux distributions
    6.3, 6.4, 7.0 and 7.1 fixes all known problems in the samba package.
    For the recently released SuSE-7.2 distribution we provide an update
    package to the version 2.2.0a.

    We thank Martin Walter, CC university of Freiburg, for his helpful
    contribution in debugging the Large File Support (LSF) of the 7.1

    * We have removed the samba packages from the update trees for the 6.0,
    6.1 and 6.2 distributions on our ftp-server. These packages would
    introduce security risks if installed on a host.
    * The samba source rpm package in distributions after and including 7.0
    generates both the samba.rpm and the smbclnt.rpm package. It is
    recommended to update both packages for these distributions.

    Please download the update package from locations described below and
    check the authenticity of the rpm package file using a method as
    described in section 3 of this security announcement.
    Use the command 'rpm -Uhv file.rpm' to apply the update.

    Special installation instructions:
    After successful installation of the update package, it is necessary to
    restart the samba server. To do this, use the following command
        rcsmb restart
    as root.

    i386 Intel Platform:

    source rpm:

    source rpm:

    source rpm:

    source rpm:

    source rpm:

    Sparc Platform:

    source rpm:

    source rpm:

    AXP Alpha Platform:

    source rpm:

    source rpm:

    source rpm:

    source rpm:

    PPC Power PC Platform:

    source rpm:

    source rpm:

    source rpm:


2) Pending vulnerabilities in SuSE Distributions and Workarounds:

  - Location of update packages on
    Licensing problems as well as US crypto-software export regulations
    keep us from publishing update packages that contain cryptographical
    software on, our US ftp server. Bandwith requirements
    keep us from moving the server to our German location. For these
    reasons, crypto-packages for SuSE Linux distributions before SuSE-7.1
    can be obtained from the equivalent tree on Distributions
    after and including SuSE-7.1 have their crypto-packages hosted on This was possible with some efforts to remove all non-free
    cryptographical algorithms from our packages.

  - qpopper
    In our last security announcement (SuSE-SA:2001:020 gpg/gnupg) we
    announced that we investigate the buffer overflow that has been found
    in qpopper versions before 4.0.3. SuSE Linux distributions are not
    affected by this bug because a different version is being used.

  - dqs has found an exploitable buffer overflow bug in
    the dsh program from the dqs package on SuSE Linux distributions.
    To workaround the problem, do "chmod -s /usr/bin/dsh" and change the
    files /etc/permissions* to reflect the change. If you do not need the
    dqs package, then deinstall it (rpm -e dqs).
    Packages for most of the supported SuSE Linux distributions are
    available at the usual location>/<dist>
    for download and installation/update. Do not forget to change the files
    /etc/permissions* to remove the suid-bit from the dsh program. Please
    note that we will not issue a dedicated security announcement for this
    specific bug.

  - pcp
    Paul Starzetz discovered a security weakness in the setuid root program
    /usr/share/pcp/bin/pmpost. The common library in pcp trusts the
    environment that has been supplied by the user, regardless of privileged
    execution or not. By consequence, a user can specify the configuration
    file and therefore write to files owned by root. The problem is not based
    on insecurely following symlinks as stated by Paul Starzetz.
    The pcp package is not installed by default in SuSE Linux distributions.
    We have provided update packages for the SuSE Linux distributions version
    7.1 and 7.2 that remove the setuid bit from the pmpost binary. Versions
    before SuSE-7.1 were not affected because the setuid bit was not set.
    We thank Keith Owens and Mark Goodwin from Silicon Graphics for responding
    quickly and for publishing a new version of the pcp package which will
    be included in future releases of the SuSE Linux distribution. For more
    information see the /usr/share/doc/packages/pcp directory of your SuSE
    Linux installation after installing the update package, or go to
    obtained from .
    Please note that there will not be a dedicated security announcement
    for this specific bug.

  - xinetd
    A buffer overflow has been found in xinetd, all versions, all
    SuSE Linux distributions. It may be abused to remotely attack a host
    running xinetd. The xinetd package is not installed by default in SuSE
    Linux distributions. Manual interaction must have been applied to run
    the daemon.
    Update packages can be found at the usual location on our ftp server.
    The security announcement for this security problem is underway.

  - fetchmail (fetchml)
    New fetchmail packages are available on the ftp server. The packages
    cure a buffer overflow that can be exploited by sending a victim a
    specially designed email, waiting for the victim's fetchmail program
    to pick up the email. We are preparing a security announcement for this

  - openssh
    update packages for the openssh package after (and including) SuSE-6.4
    are available on our ftp servers (for < 7.1) or (for >= 7.1). We are currently checking for a non-security
    related irregularity in sshd's behaviour under faulty setup conditions.

  - exim
    SuSE Linux distributions do not contain the exim Mail Transport Agent
    (See for details) and are therefore not susceptible
    to the recently found security-related bugs.

  - webmin
    SuSE Linux distributions do not contain the webmin administration
    web frontend (See for details) and are therefore
    not vulnerable to the recently found security-related problems in the


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,
       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 uninstalled rpm
       package file.
        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 "" upon installation or upgrade, provided that
           the package gpg is installed. The file containing the public key
           is placed at the toplevel directory of the first CD (pubring.gpg)
           and at .

  - SuSE runs two security mailing lists to which any interested party may
        - general/linux/SuSE security discussion.
            All SuSE security announcements are sent to this list.
            To subscribe, send an email to
        - SuSE's announce-only mailing list.
            Only SuSE's security annoucements are sent to this list.
            To subscribe, send an email to

    For general information or the frequently asked questions (faq)
    send mail to:
        <> or
        <> respectively.

    SuSE's security contact is <>.
    The <> 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 cleartext signature shows proof of the
    authenticity of the text.
    SuSE GmbH 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 <>
pub 1024D/9C800ACA 2000-10-19 SuSE Package Signing Key <>

Version: GnuPG v1.0.6 (GNU/Linux)
Comment: For info see


Version: 2.6.3i
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