[Full-Disclosure] Fwd: CERT Advisory CA-2003-12 Buffer Overflow in Sendmail

From: Muhammad Faisal Rauf Danka (mfrd@attitudex.com)
Date: 03/30/03

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    From: Muhammad Faisal Rauf Danka <mfrd@attitudex.com>
    To: bugtraq@securityfocus.com
    Date: Sun, 30 Mar 2003 11:04:19 -0800 (PST)
    

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    Muhammad Faisal Rauf Danka

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    Date: Sat, 29 Mar 2003 14:57:34 -0500
    From: CERT Advisory <cert-advisory@cert.org>
    To: cert-advisory@cert.org
    
    

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    CERT Advisory CA-2003-12 Buffer Overflow in Sendmail

       Original release date: March 29, 2003
       Last revised:
       Source: CERT/CC

       A complete revision history can be found at the end of this file.

    Systems Affected

         * Sendmail Pro (all versions)
         * Sendmail Switch 2.1 prior to 2.1.6
         * Sendmail Switch 2.2 prior to 2.2.6
         * Sendmail Switch 3.0 prior to 3.0.4
         * Sendmail for NT 2.X prior to 2.6.3
         * Sendmail for NT 3.0 prior to 3.0.4
         * Systems running open-source sendmail versions prior to 8.12.9,
           including UNIX and Linux systems

    Overview

       There is a vulnerability in sendmail that can be exploited to cause a
       denial-of-service condition and could allow a remote attacker to
       execute arbitrary code with the privileges of the sendmail daemon,
       typically root.

    I. Description

       There is a remotely exploitable vulnerability in sendmail that could
       allow an attacker to gain control of a vulnerable sendmail server.
       Address parsing code in sendmail does not adequately check the length
       of email addresses. An email message with a specially crafted address
       could trigger a stack overflow. This vulnerability was discovered by
       Michal Zalewski.

       This vulnerability is different than the one described in CA-2003-07.

       Most organizations have a variety of mail transfer agents (MTAs) at
       various locations within their network, with at least one exposed to
       the Internet. Since sendmail is the most popular MTA, most
       medium-sized to large organizations are likely to have at least one
       vulnerable sendmail server. In addition, many UNIX and Linux
       workstations provide a sendmail implementation that is enabled and
       running by default.

       This vulnerability is message-oriented as opposed to
       connection-oriented. That means that the vulnerability is triggered by
       the contents of a specially-crafted email message rather than by
       lower-level network traffic. This is important because an MTA that
       does not contain the vulnerability will pass the malicious message
       along to other MTAs that may be protected at the network level. In
       other words, vulnerable sendmail servers on the interior of a network
       are still at risk, even if the site's border MTA uses software other
       than sendmail. Also, messages capable of exploiting this vulnerability
       may pass undetected through many common packet filters or firewalls.

       This vulnerability has been successfully exploited to cause a
       denial-of-service condition in a laboratory environment. It is
       possible that this vulnerability could be used to execute code on some
       vulnerable systems.

       The CERT/CC is tracking this issue as VU#897604. This reference number
       corresponds to CVE candidate CAN-2003-0161.

       For more information, please see

              http://www.sendmail.org
              http://www.sendmail.org/8.12.9.html
              http://www.sendmail.com/security/

       For the latest information about this vulnerability, including the
       most recent vendor information, please see

              http://www.kb.cert.org/vuls/id/897604

       This vulnerability is distinct from VU#398025.

    II. Impact

       Successful exploitation of this vulnerability may cause a
       denial-of-service condition or allow an attacker to gain the
       privileges of the sendmail daemon, typically root. Even vulnerable
       sendmail servers on the interior of a given network may be at risk
       since the vulnerability is triggered by the contents of a malicious
       email message.

    III. Solution

    Apply a patch from Sendmail, Inc.

       Sendmail has produced patches for versions 8.9, 8.10, 8.11, and 8.12.
       However, the vulnerability also exists in earlier versions of the
       code; therefore, site administrators using an earlier version are
       encouraged to upgrade to 8.12.9. These patches, and a signature file,
       are located at

              ftp://ftp.sendmail.org/pub/sendmail/prescan.tar.gz.uu
              ftp://ftp.sendmail.org/pub/sendmail/prescan.tar.gz.uu.asc

    Apply a patch from your vendor

       Many vendors include vulnerable sendmail servers as part of their
       software distributions. We have notified vendors of this vulnerability
       and recorded the statements they provided in Appendix A of this
       advisory. The most recent vendor information can be found in the
       systems affected section of VU#897604.

    Enable the RunAsUser option

       There is no known workaround for this vulnerability. Until a patch can
       be applied, you may wish to set the RunAsUser option to reduce the
       impact of this vulnerability. As a good general practice, the CERT/CC
       recommends limiting the privileges of an application or service
       whenever possible.

    Appendix A. - Vendor Information

       This appendix contains information provided by vendors for this
       advisory. As vendors report new information to the CERT/CC, we will
       update this section and note the changes in our revision history. If a
       particular vendor is not listed below, we have not received their
       comments.

    Red Hat Inc.

       Red Hat distributes sendmail in all Red Hat Linux distributions. We
       are currently [Mar29] working on producing errata packages to correct
       this issue, when complete these will be available along with our
       advisory at the URL below. At the same time users of the Red Hat
       Network will be able to update their systems using the 'up2date' tool.

       Red Hat Linux:

              http://rhn.redhat.com/errata/RHSA-2003-120.html

       Red Hat Enterprise Linux:

              http://rhn.redhat.com/errata/RHSA-2003-121.html

    The Sendmail Consortium

       The Sendmail Consortium recommends that sites upgrade to 8.12.9
       whenever possible. Alternatively, patches are available for 8.9, 8.10,
       8.11, and 8.12 on http://www.sendmail.org/.

    Sendmail, Inc.

       All commercial releases including Sendmail Switch, Sendmail Advanced
       Message Server (which includes the Sendmail Switch MTA), Sendmail for
       NT, and Sendmail Pro are affected by this issue. Patch information is
       available at http://www.sendmail.com/security/.
         _________________________________________________________________

       Our thanks to Eric Allman, Claus Assmann, Greg Shapiro, and Dave
       Anderson of Sendmail for reporting this problem and for their
       assistance in coordinating the response to this problem. We also thank
       Michal Zalewski for discovering this vulnerability.
         _________________________________________________________________

       Authors: Art Manion and Shawn V. Hernan
       ______________________________________________________________________

       This document is available from:
       http://www.cert.org/advisories/CA-2003-12.html
       ______________________________________________________________________

    CERT/CC Contact Information

       Email: cert@cert.org
              Phone: +1 412-268-7090 (24-hour hotline)
              Fax: +1 412-268-6989
              Postal address:
              CERT Coordination Center
              Software Engineering Institute
              Carnegie Mellon University
              Pittsburgh PA 15213-3890
              U.S.A.

       CERT/CC personnel answer the hotline 08:00-17:00 EST(GMT-5) /
       EDT(GMT-4) Monday through Friday; they are on call for emergencies
       during other hours, on U.S. holidays, and on weekends.

    Using encryption

       We strongly urge you to encrypt sensitive information sent by email.
       Our public PGP key is available from
       http://www.cert.org/CERT_PGP.key

       If you prefer to use DES, please call the CERT hotline for more
       information.

    Getting security information

       CERT publications and other security information are available from
       our web site
       http://www.cert.org/

       To subscribe to the CERT mailing list for advisories and bulletins,
       send email to majordomo@cert.org. Please include in the body of your
       message

       subscribe cert-advisory

       * "CERT" and "CERT Coordination Center" are registered in the U.S.
       Patent and Trademark Office.
       ______________________________________________________________________

       NO WARRANTY
       Any material furnished by Carnegie Mellon University and the Software
       Engineering Institute is furnished on an "as is" basis. Carnegie
       Mellon University makes no warranties of any kind, either expressed or
       implied as to any matter including, but not limited to, warranty of
       fitness for a particular purpose or merchantability, exclusivity or
       results obtained from use of the material. Carnegie Mellon University
       does not make any warranty of any kind with respect to freedom from
       patent, trademark, or copyright infringement.
         _________________________________________________________________

       Conditions for use, disclaimers, and sponsorship information

       Copyright 2003 Carnegie Mellon University.
       Revision History

       March 29,2003: Initial release

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