SuSe: lpr arbitrary commands vulnerability

    Date31 Oct 2002
    CategorySuSE
    2482
    Posted ByLinuxSecurity Advisories
    There is a vulnerability where local attackers can pass certain commandline arguments to lpr running as root, fooling it to execute arbitrary commands as root.
    
    ______________________________________________________________________________
    
                            SuSE Security Announcement
    
            Package:                lprng, html2ps
            Announcement-ID:        SuSE-SA:2002:040
            Date:                   Thu Oct 31 11:00:10 MET 2002
            Affected products:      7.0, 7.1, 7.2, 7.3, 8.0, 8.1
                                    SuSE eMail Server III, 3.1
                                    SuSE Firewall on CD/Admin host
                                    SuSE Firewall on CD 2
                                    SuSE Linux Connectivity Server
                                    SuSE Linux Enterprise Server 7
                                    SuSE Linux Office Server
            Vulnerability Type:     local privilege escalation,
                                    remote command execution
            Severity (1-10):        6
            SuSE default package:   yes
            Cross References:       -
    
        Content of this advisory:
            1) security vulnerability resolved: Local privilege escalation in
                runlpr (from lprng package) and remote command execution
                via html2ps printfilter.
               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
    
        The lprng package contains the "runlpr" program which allows the lp
        user to execute the lpr program as root. Local attackers can pass
        certain commandline arguments to lpr running as root, fooling it
        to execute arbitrary commands as root. This has been fixed.
        Note that this vulnerability can only be exploited if the attacker
        has previously gained access to the lp account.
    
        Additionally, the html2ps printfilter, which is installed as part of
        the LPRng print system, allowed remote attackers to execute arbitrary
        commands in the context of the lp user.
    
        These two issues combined allow attackers to mount a remote root attack.
    
        As a workaround, we recommend to uninstall the html2ps package, and
        restrict access to your print services to authorized hosts only.
    
        Access control to lpd is implemented by adding appropriate entries to the
        /etc/lpd.perms file. Please consult the lpd.perms(5) manpage, or add the
        single line
    
          DEFAULT REJECT
    
        to your /etc/lpd.perms file to deny access to everyone from the outside.
    
    
        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-8.1
         ftp://ftp.suse.com/pub/suse/i386/update/8.1/rpm/i586/html2ps-1.0b3-458.i586.rpm
          c1990d8139e33176fb02745f3e5b0a05
        source rpm:
         ftp://ftp.suse.com/pub/suse/i386/update/8.1/rpm/src/html2ps-1.0b3-458.src.rpm
          f42f18d885dc2fe5701bc74812fd6ceb
    
         ftp://ftp.suse.com/pub/suse/i386/update/8.1/rpm/i586/lpdfilter-0.43-63.i586.rpm
          cc79a87fd8fcc9cf92356ab4863babc6
        source rpm:
         ftp://ftp.suse.com/pub/suse/i386/update/8.1/rpm/src/lpdfilter-0.43-63.src.rpm
          0ad433931936c4ba5a644de9104b3db4
    
        SuSE-8.0
         ftp://ftp.suse.com/pub/suse/i386/update/8.0/gra1/html2ps-1.0b3-456.i386.rpm
          c14c59d1f23575841a95f7d5eaf6f734
        source rpm:
         ftp://ftp.suse.com/pub/suse/i386/update/8.0/zq1/html2ps-1.0b3-456.src.rpm
          7ffd5b01e399ee427a0d3a16d15af4f1
    
         ftp://ftp.suse.com/pub/suse/i386/update/8.0/ap1/lpdfilter-0.42-155.i386.rpm
          dd04dd60c4c18b5711643f6334b97bfd
        source rpm:
         ftp://ftp.suse.com/pub/suse/i386/update/8.0/zq1/lpdfilter-0.42-155.src.rpm
          4d6b611c572d251f47c0b4cf8ab7a28d
    
        SuSE-7.3
         ftp://ftp.suse.com/pub/suse/i386/update/7.3/gra1/html2ps-1.0b3-457.i386.rpm
          28a1aee8dfedfff3eb348fc4ea4a8876
        source rpm:
         ftp://ftp.suse.com/pub/suse/i386/update/7.3/zq1/html2ps-1.0b3-457.src.rpm
          2765c61e39616199cbf5066d719280b3
    
        SuSE-7.2
         ftp://ftp.suse.com/pub/suse/i386/update/7.2/gra1/html2ps-1.0b1-432.i386.rpm
          1ab553d151c65505184353ae6e514db6
        source rpm:
         ftp://ftp.suse.com/pub/suse/i386/update/7.2/zq1/html2ps-1.0b1-432.src.rpm
          b71dba7782caeb01954b418e3ffdd6c2
    
        SuSE-7.1
         ftp://ftp.suse.com/pub/suse/i386/update/7.1/gra1/html2ps-1.0b1-431.i386.rpm
          1d9adfc7cc1e141f340b844f040bfe85
        source rpm:
         ftp://ftp.suse.com/pub/suse/i386/update/7.1/zq1/html2ps-1.0b1-431.src.rpm
          b1b29ff154fc13cb806dec49fc00ff81
    
        SuSE-7.0
         ftp://ftp.suse.com/pub/suse/i386/update/7.0/gra1/html2ps-1.0b1-428.i386.rpm
          7e0bd236c647cd70ba9b0274f7b5cf53
        source rpm:
         ftp://ftp.suse.com/pub/suse/i386/update/7.0/zq1/html2ps-1.0b1-428.src.rpm
          b60e012d057e428e6ade468d46afd4e5
    
    
        Sparc Platform:
        SuSE-7.3
         ftp://ftp.suse.com/pub/suse/sparc/update/7.3/gra1/html2ps-1.0b3-88.sparc.rpm
          b6c1c7399a041477ce0c321a9eda383b
        source rpm:
         ftp://ftp.suse.com/pub/suse/sparc/update/7.3/zq1/html2ps-1.0b3-88.src.rpm
          8102e2145e43fb6486cee5ccfc106c67
    
    
        AXP Alpha Platform:
    
        SuSE-7.0
         ftp://ftp.suse.com/pub/suse/axp/update/7.0/gra1/html2ps-1.0b1-328.alpha.rpm
          83967dc5d7dcf672c6dd902c125a3e81
        source rpm:
         ftp://ftp.suse.com/pub/suse/axp/update/7.0/zq1/html2ps-1.0b1-328.src.rpm
          e3851c0f69017811168213a707431467
    
    
        PPC Power PC Platform:
    
        SuSE-7.1
         ftp://ftp.suse.com/pub/suse/ppc/update/7.1/gra1/html2ps-1.0b1-303.ppc.rpm
          b9cb5de37503927812f767a0781bfc6a
        source rpm:
         ftp://ftp.suse.com/pub/suse/ppc/update/7.1/zq1/html2ps-1.0b1-303.src.rpm
          be58c62e270d5cbc2aa3395beae91009
    
        SuSE-7.0
         ftp://ftp.suse.com/pub/suse/ppc/update/7.0/gra1/html2ps-1.0b1-302.ppc.rpm
          a98f5628ae1068b3d7f20b83ace9bb77
        source rpm:
         ftp://ftp.suse.com/pub/suse/ppc/update/7.0/zq1/html2ps-1.0b1-302.src.rpm
          5a425dbc64f2e0f2a368ecb566c624eb
    
    
    ______________________________________________________________________________
    
    2)  Pending vulnerabilities in SuSE Distributions and Workarounds:
    
        There is no additional information this time.
    
    ______________________________________________________________________________
    
    
    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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