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SuSE: local privilege escalation in sudo

The sudo program allows local users to execute certain configured commands with root priviledges. Sudo contains a heap overflow in its prompt assembling function. The input used to create the password prompt is user controlled and not properly length-checked before copied to certain heap locations. This allows local attackers to overflow the heap of sudo, thus executing arbitrary commands as root. We would like to thank GlobalInterSec for finding and researching this vulnerability. Fixed packages are available from ftp.suse.com.
-----BEGIN PGP SIGNED MESSAGE-----

______________________________________________________________________________

                        SuSE Security Announcement

        Package:                sudo
        Announcement-ID:        SuSE-SA:2002:014
        Date:                   Tue Apr 30 16:00:00 MEST 2002
        Affected products:      6.4, 7.0, 7.1, 7.2, 7.3, 8.0,
                                SuSE Firewall Adminhost VPN,
                                SuSE Linux Admin-CD for Firewall,
                                SuSE Linux Enterprise Server,
                                SuSE Linux Connectivity Server
        Vulnerability Type:     local privilege escalation
        Severity (1-10):        6
        SuSE default package:   yes
        Other affected systems: All systems with sudo installed.

    Content of this advisory:
        1) security vulnerability resolved: Heap overflow in sudo.
           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 sudo program allows local users to execute certain configured
    commands with root priviledges. Sudo contains a heap overflow in its
    prompt assembling function. The input used to create the password prompt
    is user controlled and not properly length-checked before copied to certain
    heap locations. This allows local attackers to overflow the heap of sudo,
    thus executing arbitrary commands as root.
        We would like to thank GlobalInterSec for finding and researching
    this vulnerability.
        As a temporary workaround you may remove the setuid bit from sudo by
    issuing the following command as root: "chmod -s /usr/bin/sudo".

    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-8.0
    ftp://ftp.suse.com/pub/suse/i386/update/8.0/ap1/sudo-1.6.5p2-79.i386.rpm
      b54f68ff4b32f9d920f2f1ff887d1ddc
    source rpm:
    ftp://ftp.suse.com/pub/suse/i386/update/8.0/zq1/sudo-1.6.5p2-79.src.rpm
      fd1ccf6fe52c6b999c5ed24a2f3a4e65

    SuSE-7.3
    ftp://ftp.suse.com/pub/suse/i386/update/7.3/ap1/sudo-1.6.3p7-83.i386.rpm
      80edbf5caf02c519cf2c01d6ba76d22f
    source rpm:
    ftp://ftp.suse.com/pub/suse/i386/update/7.3/zq1/sudo-1.6.3p7-83.src.rpm
      77962932840740ce5e3dfe57a887592d

    SuSE-7.2
    ftp://ftp.suse.com/pub/suse/i386/update/7.2/ap1/sudo-1.6.3p6-92.i386.rpm
      669aa8db134e39f462cb9f2648f6735f
    source rpm:
    ftp://ftp.suse.com/pub/suse/i386/update/7.2/zq1/sudo-1.6.3p6-92.src.rpm
      249b1ef0135dcfede3648982900e277c

    SuSE-7.1
    ftp://ftp.suse.com/pub/suse/i386/update/7.1/ap1/sudo-1.6.3p6-91.i386.rpm
      6b3b84f0a4c687e91da179937b87048a
    source rpm:
    ftp://ftp.suse.com/pub/suse/i386/update/7.1/zq1/sudo-1.6.3p6-91.src.rpm
      bf59a6b200a0fb130f3528ce23698be0

    SuSE-7.0
    ftp://ftp.suse.com/pub/suse/i386/update/7.0/ap1/sudo-1.6.3p6-90.i386.rpm
      5b67ef9fed383242111953d942c62174
    source rpm:
    ftp://ftp.suse.com/pub/suse/i386/update/7.0/zq1/sudo-1.6.3p6-90.src.rpm
      c35f6390b360500b7b649e4590a748cc

    SuSE-6.4
    ftp://ftp.suse.com/pub/suse/i386/update/6.4/ap1/sudo-1.5.9p1-87.i386.rpm
      82d98116eccc73c7a0ce03a51e9b5378
    source rpm:
    ftp://ftp.suse.com/pub/suse/i386/update/6.4/zq1/sudo-1.5.9p1-87.src.rpm
      e75e2608036a963a7339fe4632a2550b

    Sparc Platform:

    SuSE-7.3
    ftp://ftp.suse.com/pub/suse/sparc/update/7.3/ap1/sudo-1.6.3p7-33.sparc.rpm
      bd492b6d601ceb30486e3e970a2211a3
    source rpm:
    ftp://ftp.suse.com/pub/suse/sparc/update/7.3/zq1/sudo-1.6.3p7-33.src.rpm
      d2435d180cdd76647e1f1416e93c2420

    SuSE-7.1
    ftp://ftp.suse.com/pub/suse/sparc/update/7.1/ap1/sudo-1.6.3p6-37.sparc.rpm
      bbad36265f93fac25d59f8c26b1ccd52
    source rpm:
    ftp://ftp.suse.com/pub/suse/sparc/update/7.1/zq1/sudo-1.6.3p6-37.src.rpm
      a328d2eb0fdc816341a68febfeb5a33a

    SuSE-7.0
    ftp://ftp.suse.com/pub/suse/sparc/update/7.0/ap1/sudo-1.6.3p6-36.sparc.rpm
      48e7b360b45bae0b3e9e90b3bf945f75
    source rpm:
    ftp://ftp.suse.com/pub/suse/sparc/update/7.0/zq1/sudo-1.6.3p6-36.src.rpm
      bd8f11a8916340e0d243ae1cc647df26

    AXP Alpha Platform:

    SuSE-7.1
    ftp://ftp.suse.com/pub/suse/axp/update/7.1/ap1/sudo-1.6.3p6-40.alpha.rpm
      4505dd58fe309ef0a4515db6a6980ec4
    source rpm:
    ftp://ftp.suse.com/pub/suse/axp/update/7.1/zq1/sudo-1.6.3p6-40.src.rpm
      85dfbe40da4d93d54d3c16f6489a7f32

    SuSE-7.0
    ftp://ftp.suse.com/pub/suse/axp/update/7.0/ap1/sudo-1.6.3p6-40.alpha.rpm
      b67858459774e5e04c9c22e84d5899ff
    source rpm:
    ftp://ftp.suse.com/pub/suse/axp/update/7.0/zq1/sudo-1.6.3p6-40.src.rpm
      6d0537068d16785bfdbca936c6395abb

    PPC Power PC Platform:

    SuSE-7.3
    ftp://ftp.suse.com/pub/suse/ppc/update/7.3/ap1/sudo-1.6.3p7-65.ppc.rpm
      1734f578b1fa87c26e51a11e3dc90d18
    source rpm:
    ftp://ftp.suse.com/pub/suse/ppc/update/7.3/zq1/sudo-1.6.3p7-65.src.rpm
      ebff8b3e7b86ef9bb69fb13da37903ce

    SuSE-7.1
    ftp://ftp.suse.com/pub/suse/ppc/update/7.1/ap1/sudo-1.6.3p6-45.ppc.rpm
      4318adbde184c1c8fff6eb581f02c11e
    source rpm:
    ftp://ftp.suse.com/pub/suse/ppc/update/7.1/zq1/sudo-1.6.3p6-45.src.rpm
      771f9e7f6d1fc1ba4df119147e48ddcd

    SuSE-7.0
    ftp://ftp.suse.com/pub/suse/ppc/update/7.0/ap1/sudo-1.6.3p6-45.ppc.rpm
      6ae150cfa793f20e49ed751aa686fdea
    source rpm:
    ftp://ftp.suse.com/pub/suse/ppc/update/7.0/zq1/sudo-1.6.3p6-45.src.rpm
      ede5fedf45ffe6b59c43e082fcef50f4

    SuSE-6.4
    ftp://ftp.suse.com/pub/suse/ppc/update/6.4/ap1/sudo-1.5.9p1-85.ppc.rpm
      0677a205615f631a41ca308be03db7bd
    source rpm:
    ftp://ftp.suse.com/pub/suse/ppc/update/6.4/zq1/sudo-1.5.9p1-85.src.rpm
      71da4a7d43043b20eefd5e05048616d8



______________________________________________________________________________

2)  Pending vulnerabilities in SuSE Distributions and Workarounds:

    - ifup-dhcp could be tricked into executing arbitrary
    commands as root by DHCP servers handing out illegal values (e.g.
    containing spaces), because it sourced dhcpcd's info file, where
    not all variable values are quoted. This problem has been fixed.

______________________________________________________________________________

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 security@suse.de),
       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 uninstalled 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 "build@suse.de" 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 ftp://ftp.suse.com/pub/suse/pubring.gpg-build.suse.de .


  - SuSE runs two security mailing lists to which any interested party may
    subscribe:

    suse-security@suse.com
        -   general/linux/SuSE security discussion.
            All SuSE security announcements are sent to this list.
            To subscribe, send an email to
                .

    suse-security-announce@suse.com
        -   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  or .
    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 

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-- 
~
~ perl self.pl
~ $_='print"\$_=\47$_\47;eval"';eval
~ krahmer@suse.de - SuSE Security Team
~
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