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CERT Advisory CA-99-12 Buffer Overflow in amd



   Original release date: September 16, 1999

   Last revised: --

   Source: CERT/CC

   

   A complete revision history is at the end of this file.

   

Systems Affected



     * Systems running amd, the Berkeley Automounter Daemon

       

I. Description



   There is a buffer overflow vulnerability in the logging facility of

   the amd daemon.

   

   This daemon automatically mounts file systems in response to attempts

   to access files that reside on those file systems. Similar

   functionality on some systems is provided by a daemon named

   automountd.

   

   Systems that include automounter daemons based on BSD 4.x source code

   may also be vulnerable. A vulnerable implementation of amd is included

   in the am-utils package, provided with many Linux distributions.

   

II. Impact



   Remote intruders can execute arbitrary code as the user running the

   amd daemon (usually root).

   

III. Solution



Install a patch from your vendor



   Appendix A contains information provided by vendors for this advisory.

   We will update the appendix as we receive more information. If you do

   not see your vendor's name, the CERT/CC did not hear from that vendor.

   Please contact your vendor directly.

   

   We will update this advisory as more information becomes available.

   Please check the CERT/CC Web site for the most current revision.

   

Disable amd



   If you are unable to apply a patch for this problem, you can disable

   the amd daemon to prevent this vulnerability from being exploited.

   Disabling amd may prevent your system from operating normally.

   

Appendix A. Vendor Information



BSDI



   BSD/OS 4.0.1 and 3.1 are both vulnerable to this problem if amd has

   been configured. The amd daemon is not started if it has not been

   configured locally. Mods (M410-017 for 4.0.1 and M310-057) are

   available via ftp from http://ftp.bsdi.com/bsdi/patches or via our web

   site at http://www.bsdi.com/support/patches

   

Compaq Computer Corporation



   Not vulnerable

   

Data General



   DG/UX is not vulnerable to this problem.

   

Erez Zadok (am-utils maintainer)



   The latest stable version of am-utils includes several important

   security fixes. To retrieve it, use anonymous ftp for the following

   URL

   

   http://shekel.mcl.cs.columbia.edu/pub/am-utils/

          

   The MD5 checksum of the am-utils-6.0.1.tar.gz archive is

   

   MD5 (am-utils-6.0.1.tar.gz) = ac33a4394d30efb4ca47880cc5703999

          

   The simplest instructions to build, install, and run am-utils are as

   follows:

    1. Retrieve the package via FTP.

    2. Unpack it:

       $ gunzip am-utils-6.0.1.tar.gz

       $ tar xf am-utils-6.0.1.tar

       If you have GNU tar and gunzip, you can issue a single command:

       $ tar xzf am-utils-6.0.1.tar.gz

    3. Build it:

       $ cd am-utils-6.0.1

       $ ./buildall

       This would configure and build am-utils for installation in

       /usr/local. If you built am-utils in the past using a different

       procedure, you may repeat that procedure instead. For example, to

       build am-utils using shared libraries and to enable debugging, use

       either:

       $ ./buildall -Ds -b

       or

       $ ./configure --enable-debug=yes --enable-shared --disable-static

       You may run "./configure --help" to get a full list of available

       options. You may run "./buildall -H" to get a full list of options

       it offers. The buildall script is a simple wrapper script that

       configures and builds am-utils for the most common desired

       configurations.

    4. Install it:

       $ make install

       This would install the programs, scripts, libraries, manual pages,

       and info pages in /usr/local/{sbin,bin,lib,man,info}, etc.

    5. Run it.

       Assuming you have an Amd configuration file in /etc/amd.conf, you

       can simply run:

       $ /usr/local/sbin/ctl-amd restart

       That will stop the older running Amd, and start a new one. If you

       use a different Amd start-up script, you may use it instead.

       

FreeBSD



   Please see the FreeBSD advisory at

   

   http://ftp.freebsd.org/pub/FreeBSD/CERT/advisories/FreeBSD-SA-99:06.amd

          .asc

          

   for information on patches for this problem.

   

Fujitsu



   This vulnerability is still under investigation by Fujitsu.

   

Hewlett-Packard Company



   HP is not vulnerable.

   

IBM Corporation



   AIX is not vulnerable. It does not ship the am-utils package.

   

OpenBSD



   OpenBSD is not vulnerable.

   

RedHat Inc.



   RedHat has released a security advisory on this topic. It is available

   from our ftp server at:

   

   http://www.redhat.com/corp/support/errata/RHSA1999032_O1.html

          

SCO Unix



   No SCO products are vulnerable.

   

SGI



   SGI does not distribute am-utils in either IRIX or UNICOS operating

   systems.

   

Sun Microsystems, Inc.



   SunOS - All versions are not vulnerable.

   

   Solaris - All versions are not vulnerable.

     _________________________________________________________________

   

   The CERT Coordination Center would like to thank Erez Zadok, the

   maintainer of the am-utils package, for his assistance in preparing

   this advisory.

   ______________________________________________________________________

   

   This document is available from:

   http://www.cert.org/advisories/CA-99-12-amd.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 personnel answer the hotline 08:00-20:00 EST(GMT-5) / EDT(GMT-4)

   Monday through Friday; they are on call for emergencies during other

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Using encryption



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

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Getting security information



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   Copyright 1999 Carnegie Mellon University.

   Conditions for use, disclaimers, and sponsorship information can be

   found in

   

   http://www.cert.org/legal_stuff.html

       

   * "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

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     _________________________________________________________________

   

   Revision History

Sep 16, 1999:  Initial release



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