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-----BEGIN PGP SIGNED MESSAGE----- =========================================================================== AUSCERT External Security Bulletin Redistribution ESB-1999.170 -- CERT Advisory CA-99-14 Multiple Vulnerabilities in BIND 11 November 1999 =========================================================================== The CERT Coordination Centre has released the following advisory concerning multiple vulnerabilities in BIND. Remote users may execute arbitrary code with the privilege of the named daemon or impair normal operation of the daemon on systems with vulnerable versions of BIND. Under certain circumstances these vulnerabilities may allow remote users to gain root access or to perform Denial of Service (DoS) attacks against vulnerable systems. These vulnerabilities differ from those previously reported in the DNS Denial of Service related AusCERT Alert AL-1999.004. - --------------------------BEGIN INCLUDED TEXT-------------------- - -----BEGIN PGP SIGNED MESSAGE----- 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: ftp://ftp.auscert.org.au/pub/auscert/advisory/AL-1999.004.dns_dos 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 Caldera See ftp://ftp.calderasystems.com/pub/OpenLinux/updates/2.3/current MD5s 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: http://aix.software.ibm.com/aix.us/swfixes/ or send e-mail to firstname.lastname@example.org 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 http://www.isc.org/products/BIND/bind-security-19991108.html The ISC advisory also includes a table summarizing which versions of BIND are susceptible to the vulnerabilities described in this advisory. OpenBSD 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 investigating. 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: http://www.cert.org/advisories/CA-99-14-bind.html ______________________________________________________________________ CERT/CC Contact Information Email: email@example.com 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 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 be added to our mailing list for advisories and bulletins, send email to firstname.lastname@example.org and include SUBSCRIBE your-email-address in the subject of your message. 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 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. _________________________________________________________________ Revision History November 10, 1999: Initial release - -----BEGIN PGP SIGNATURE----- Version: PGP for Personal Privacy 5.0 Charset: noconv iQA/AwUBOCo3W1r9kb5qlZHQEQIY9QCgjh17l5yAtNrLFSSj2EJ3HYUe8hgAoOol 1lRvWBJAlYs63OEqqJ+mCfr2 =bBA/ - -----END PGP SIGNATURE----- - --------------------------END INCLUDED TEXT-------------------- This security bulletin is provided as a service to AusCERT's members. As AusCERT did not write the document quoted above, AusCERT has had no control over its content. The decision to use any or all of this information is the responsibility of each user or organisation, and should be done so in accordance with site policies and procedures. NOTE: This is only the original release of the security bulletin. It will not be updated when updates to the original are made. If downloading at a later date, it is recommended that the bulletin is retrieved directly from the original authors to ensure that the information is still current. Contact information for the authors of the original document is included in the Security Bulletin above. If you have any questions or need further information, please contact them directly. Previous advisories and external security bulletins can be retrieved from: http://www.auscert.org.au/Information/advisories.html If you believe that your system has been compromised, contact AusCERT or your representative in FIRST (Forum of Incident Response and Security Teams). Internet Email: email@example.com Facsimile: (07) 3365 7031 Telephone: (07) 3365 4417 (International: +61 7 3365 4417) AusCERT personnel answer during Queensland business hours which are GMT+10:00 (AEST). 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