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Home : Advisories : Multiple Vulnerabilities in BIND

Title: Multiple Vulnerabilities in BIND
Released by: CERT
Date: 10th November 1999
Printable version: Click here

Hash: SHA1

CERT Advisory CA-99-14 Multiple Vulnerabilities in BIND

   Original release date: November 10, 1999

   Last revised: --

   Source: CERT/CC


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


Systems Affected

     * Systems running various versions of BIND


I. Description

   Six vulnerabilities have been found in BIND, the popular domain name

   server from the Internet Software Consortium (ISC). One of these

   vulnerabilities may allow remote intruders to gain privileged access

   to name servers.


Vulnerability #1: the "nxt bug"

   Some versions of BIND fail to properly validate NXT records. This

   improper validation could allow an intruder to overflow a buffer and

   execute arbitrary code with the privileges of the name server.


   NXT record support was introduced in BIND version 8.2. Prior versions

   of BIND, including 4.x, are not vulnerable to this problem. The

   ISC-supplied version of BIND corrected this problem in version 8.2.2.


Vulnerability #2: the "sig bug"

   This vulnerability involves a failure to properly validate SIG

   records, allowing a remote intruder to crash named; see the impact

   section for additional details.


   SIG record support is found in multiple versions of BIND, including

   4.9.5 through 8.x.


Vulnerability #3: the "so_linger bug"

   By intentionally violating the expected protocols for closing a TCP

   session, remote intruders can cause named to pause for periods up to

   120 seconds.


Vulnerability #4: the "fdmax bug"

   Remote intruders can consume more file descriptors than BIND can

   properly manage, causing named to crash.


Vulnerability #5: the "maxdname bug"

   Improper handling of certain data copied from the network could allow

   a remote intruder to disrupt the normal operation of your name server,

   possibly including a crash.


Vulnerability #6: the "naptr bug"

   Some versions of BIND fail to validate zone information loaded from

   disk files. In environments with unusual combinations of permissions

   and protections, this could allow an intruder to crash named.


Other recent BIND-related vulnerabilities

   AusCERT recently published a report describing denial-of-service

   attacks against name servers. These attacks are unrelated to the

   issues described in this advisory. For information on the

   denial-of-service attacks described by AusCERT, please see AusCERT

   Alert AL-1999.004 available at:




II. Impact

Vulnerability #1

   By exploiting this vulnerability, remote intruders can execute

   arbitrary code with the privileges of the user running named,

   typically root.


Vulnerabilities #2, #4, and #5

   By exploiting these vulnerabilities, remote intruders can disrupt the

   normal operation of your name server, possibly causing a crash.


Vulnerability #3

   By periodically exercising this vulnerability, remote intruders can

   disrupt the ability of your name server to respond to legitimate

   queries. By intermittently exercising this vulnerability, intruders

   can seriously degrade the performance of your name server.


Vulnerability #6

   Local intruders who gain write access to your zone files can cause

   named to crash.


III. Solution

Apply a patch from your vendor or update to a later version of BIND

   Many operating system vendors distribute BIND with their operating

   system. Depending on your support procedures, arrangements, and

   contracts, you may wish to obtain BIND from your operating system

   vendor rather than directly from ISC.


   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.


Appendix A. Vendor Information

Vendor Name


   See http://ftp.calderasystems.com/pub/OpenLinux/updates/2.3/current


        db1dda05dbe0f67c2bd2e5049096b42c  RPMS/bind-8.2.2p3-1.i386.rpm

        82bbe025ac091831904c71c885071db1  RPMS/bind-doc-8.2.2p3-1.i386.rpm

        2f9a30444046af551eafd8e6238a50c6  RPMS/bind-utils-8.2.2p3-1.i386.rpm

        0e4f041549bdd798cb505c82a8911198  SRPMS/bind-8.2.2p3-1.src.rpm

Compaq Computer Corporation

   At the time of writing this document, Compaq is currently

   investigating the potential impact to Compaq's BIND release(s).


   As further information becomes available Compaq will provide notice of

   the completion/availability of any necessary patches through AES

   services (DIA, DSNlink FLASH and posted to the Services WEB page) and

   be available from your normal Compaq Services Support channel.


Data General

   We are investigating. We will provide an update when our investigation

   is complete.


Hewlett-Packard Company

   HP is vulnerable, see the chart in the ISC advisory for details on

   your installed version of BIND. Our fix strategy is under

   investigation, watch for updates to this CERT advisory in the CERT

   archives, or an HP security advisory/bulletin.


IBM Corporation

   The bind8 shipped with AIX 4.3.x is vulnerable. We are currently

   working on the following APARs which will be available soon:


   APAR 4.3.x: IY05851


   To Order


   APARs may be ordered using Electronic Fix Distribution (via FixDist)

   or from the IBM Support Center. For more information on FixDist,

   reference URL:




   or send e-mail to aixserv@austin.ibm.com with a subject of "FixDist".


   IBM and AIX are registered trademarks of International Business

   Machines Corporation.


The Internet Software Consortium

   ISC has published an advisory regarding these problems, available at




   The ISC advisory also includes a table summarizing which versions of

   BIND are susceptible to the vulnerabilities described in this




   As far as we know, we don't ship with any of those vulnerabilities.


Santa Cruz Operation, Inc

   Security patches for the following SCO products will be made available

   at http://www.sco.com/security


   OpenServer 5.x.x, UnixWare 7.x.x, UnixWare 2.x.x


Sun Microsystems

   Vulnerability #1


   Solaris 2.3, 2.4, 2.5, 2.5.1, 2.6, and 7 are not vulnerable.


   Vulnerability #2


   Solaris 2.3, 2.4, 2.5, 2.5.1, 2.6, and 7 are not vulnerable.


   Vulnerability #3


   Solaris 2.3, 2.4, 2.5, 2.5.1, and 2.6 are not vulnerable.

          Sun will be producing patches for Solaris 7.


   Vulnerability #4


   Solaris 2.3, 2.4, 2.5, 2.5.1, and 2.6 are not vulnerable.

          Solaris 7 is probably not vulnerable. We are still



   Vulnerability #5


   Solaris 2.3, 2.4, 2.5, 2.5.1, and 2.6 are not vulnerable.

          Sun will be producing patches for Solaris 7.


   Vulnerability #6


   Solaris 2.3, 2.4, 2.5, 2.5.1, and 2.6 are not vulnerable.

          Sun will be producing patches for Solaris 7.



   The CERT Coordination Center would like to thank David Conrad, Paul

   Vixie and Bob Halley of the Internet Software Consortium for notifying

   us of these problems and for their help in constructing the advisory,

   and Olaf Kirch of Caldera for notifying us of some of these problems

   and providing technical assistance and advice.



   This document is available from:




CERT/CC Contact Information

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          Phone: +1 412-268-7090 (24-hour hotline)

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          CERT Coordination Center

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   Copyright 1999 Carnegie Mellon University.

   Conditions for use, disclaimers, and sponsorship information can be

   found in




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   Revision History

November 10, 1999:  Initial release


Version: PGP for Personal Privacy 5.0

Charset: noconv





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