Bind: FreeBSD-SA-01:10 and CERT Advisory CA-2001-02

From: Igor Roshchin (str@giganda.komkon.org)
Date: 01/29/01


From: Igor Roshchin <str@giganda.komkon.org>
To: security@freebsd.org
Date: Mon, 29 Jan 2001 11:29:51 -0500 (EST)


Two comments/questions:

1. FreeBSD-SA-01:10
(per
ftp://ftp.FreeBSD.org/pub/FreeBSD/CERT/advisories/FreeBSD-SA-01:10.bind.asc)
says:
Affects: FreeBSD 3.x prior to the correction date.
                Ports collection prior to the correction date.
Corrected: 2000-11-27 (FreeBSD 3.5-STABLE)
                2001-01-05 (Ports collection)

and then, in Problem description it explains:
All versions of FreeBSD 3.x prior to the correction date including
3.5.1-RELEASE are vulnerable to this problem. In addition, the bind8
port in the ports collection is also vulnerable. FreeBSD 4.x is not
affected since it contains versions of BIND 8.2.3.

My COMMENT:
-------
This is not true, because 4.0-RELEASE was shipped with
named 8.2.2-P5-NOESW Mon Mar 20 20:43:54 GMT 2000
        root@monster.cdrom.com:/usr/obj/usr/src/usr.sbin/named
Thus, the statement in the advisory in question might be
at least misleading.

Therefore :
My question:
Is 8.2.2-P5-NOESW (shipped with 4.0-RELEASE) vulnerable to
a) the problem described in FreeBSD-SA-01:10
b) the problem described in CERT Advisory CA-2001-02
(Multiple Vulnerabilities in BIND), VU#196945 (see that advisory
at the bottom of this message).

Since 3.5.1-RELEASE was packaged with the same version of bind:
named 8.2.2-P5-NOESW Thu Jul 20 02:01:19 GMT 2000
        jkh@monster.osd.bsdi.com:/usr/obj/usr/src/usr.sbin/named
I assume the answer to the question a) is "yes".

How about b) ?
Also "yes" ?

To the security officers:
http://www.freebsd.org/security/#adv does not show any advisories
on bind, except the one mentioned above. Will there be any advisory
addressing the problem mentioned by the CERT advisory
in regards to the older versions of FreeBSD (and BIND packaged with them)?

Thanks,

Igor

----- Forwarded message from CERT Advisory -----

[There is text before PGP section.]

-- Start of PGP signed section.
CERT Advisory CA-2001-02 Multiple Vulnerabilities in BIND

   Original release date: January 29, 2001
   Last revised: --
   Source: CERT/CC

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

Systems Affected

   Domain Name System (DNS) Servers running various versions of ISC BIND
   (including both 4.9.x prior to 4.9.8 and 8.2.x prior to 8.2.3; 9.x is
   not affected) and derivatives. Because the normal operation of most
   services on the Internet depends on the proper operation of DNS
   servers, other services could be impacted if these vulnerabilities are
   exploited.

Overview

   The CERT/CC has recently learned of four vulnerabilities spanning
   multiple versions of the Internet Software Consortium's (ISC) Berkeley
   Internet Name Domain (BIND) server. BIND is an implementation of the
   Domain Name System (DNS) that is maintained by the ISC. Because the
   majority of name servers in operation today run BIND, these
   vulnerabilities present a serious threat to the Internet
   infrastructure.

   Three of these vulnerabilities (VU#196945, VU#572183, and VU#868916)
   were discovered by the COVERT Labs at PGP Security, who have posted an
   advisory regarding these issues at

          http://www.pgp.com/research/covert/advisories/047.asp

   The fourth vulnerability (VU#325431) was discovered by Claudio
   Musmarra.

   The Internet Software Consortium has posted information about all four
   vulnerabilities at

          http://www.isc.org/products/BIND/bind-security.html

I. Description

   VU#196945 - ISC BIND 8 contains buffer overflow in transaction
   signature (TSIG) handling code

   During the processing of a transaction signature (TSIG), BIND 8 checks
   for the presence of TSIGs that fail to include a valid key. If such a
   TSIG is found, BIND skips normal processing of the request and jumps
   directly to code designed to send an error response. Because the
   error-handling code initializes variables differently than in normal
   processing, it invalidates the assumptions that later function calls
   make about the size of the request buffer.

   Once these assumptions are invalidated, the code that adds a new
   (valid) signature to the responses may overflow the request buffer and
   overwrite adjacent memory on the stack or the heap. When combined with
   other buffer overflow exploitation techniques, an attacker can gain
   unauthorized privileged access to the system, allowing the execution
   of arbitrary code.

   VU#572183 - ISC BIND 4 contains buffer overflow in nslookupComplain()

   The vulnerable buffer is a locally defined character array used to
   build an error message intended for syslog. Attackers attempting to
   exploit this vulnerability could do so by sending a specially
   formatted DNS query to affected BIND 4 servers. If properly
   constructed, this query could be used to disrupt the normal operation
   of the DNS server process, resulting in either denial of service or
   the execution of arbitrary code.

   VU#868916 - ISC BIND 4 contains input validation error in
   nslookupComplain()

   The vulnerable buffer is a locally defined character array used to
   build an error message intended for syslog. Attackers attempting to
   exploit this vulnerability could do so by sending a specially
   formatted DNS query to affected BIND 4 servers. If properly
   constructed, this query could be used to disrupt the normal operation
   of the DNS server process, resulting in the execution of arbitrary
   code.

   This vulnerability was patched by the ISC in an earlier version of
   BIND 4, most likely BIND 4.9.5-P1. However, there is strong evidence
   to suggest that some third party vendors who redistribute BIND 4 have
   not included these changes in their BIND packages. Therefore, the
   CERT/CC recommends that all users of BIND 4 or its derivatives base
   their distributions on BIND 4.9.8.

   VU#325431 - Queries to ISC BIND servers may disclose environment
   variables

   This vulnerability is an information leak in the query processing code
   of both BIND 4 and BIND 8 that allows a remote attacker to access the
   program stack, possibly exposing program and/or environment variables.
   This vulnerability is triggered by sending a specially formatted query
   to vulnerable BIND servers.

II. Impact

   VU#196945 - ISC BIND 8 contains buffer overflow in transaction
   signature (TSIG) handling code

   This vulnerability may allow an attacker to execute code with the same
   privileges as the BIND server. Because BIND is typically run by a
   superuser account, the execution would occur with superuser
   privileges.

   VU#572183 - ISC BIND 4 contains buffer overflow in nslookupComplain()

   This vulnerability can disrupt the proper operation of the BIND server
   and may allow an attacker to execute code with the privileges of the
   BIND server. Because BIND is typically run by a superuser account, the
   execution would occur with superuser privileges.

   VU#868916 - ISC BIND 4 contains input validation error in
   nslookupComplain()

   This vulnerability may allow an attacker to execute code with the
   privileges of the BIND server. Because BIND is typically run by a
   superuser account, the execution would occur with superuser
   privileges.

   VU#325431 - Queries to ISC BIND servers may disclose environment
   variables

   This vulnerability may allow attackers to read information from the
   program stack, possibly exposing environment variables. In addition,
   the information obtained by exploiting this vulnerability may aid in
   the development of exploits for VU#572183 and VU#868916.

III. History

   Since 1997, the CERT/CC has published twelve documents describing
   vulnerabilities or exploitation of vulnerabilities in BIND with
   information and advice on upgrading and preventing compromises.
   Unfortunately, many system and network administrators still have not
   upgraded their versions of BIND, making them susceptible to a number
   of vulnerabilities. Prior vulnerabilities in BIND have been widely
   exploited by intruders.

   For example, on November 10, 1999, the CERT/CC published CA-1999-14,
   which detailed multiple vulnerabilities in BIND. The CERT/CC continued
   to receive reports of compromises based on those vulnerabilities
   through December 2000. On April 8, 1998, the CERT/CC published
   CA-1998-05; reports of compromises based on the vulnerabilities
   described therein continued through November of 1998.

   The following graph shows the number of incidents reported to the
   CERT/CC regarding BIND NXT record (VU#16532) exploits after the
   publication of CA-1999-14:

       Incidents By Month Involving the BIND NXT Record Vulnerability
                                (VU#16532)

   Based on this past experience, the CERT/CC expects that intruders will
   quickly begin developing and using intruder tools to compromise
   machines. It is important for IT and security managers to ensure that
   their organizations are properly protected before the expected
   wide-spread exploitation happens.

Exploitation

   The vulnerabilities described in VU#196945, VU#572183, and VU#868916
   have been successfully exploited by COVERT Labs in a laboratory
   environment. To the best of our knowledge, no exploits have been
   released to the public.

IV. Solution

Apply a patch from your vendor

   The ISC has released BIND versions 4.9.8 and 8.2.3 to address these
   security issues. The CERT/CC recommends that users of BIND 4.9.x or
   8.2.x upgrade to BIND 4.9.8, BIND 8.2.3, or BIND 9.1.

   Because BIND 4 is no longer actively maintained, the ISC recommends
   that users affected by this vulnerability upgrade to either BIND 8.2.3
   or BIND 9.1. Upgrading to one of these versions will also provide
   functionality enhancements that are not related to security.

   The BIND 4.9.8 and 8.2.3 distributions can be downloaded from

          ftp://ftp.isc.org/isc/bind/src/

   The BIND 9.1 distribution can be downloaded from

          ftp://ftp.isc.org/isc/bind9/

   Appendix A contains information supplied by ISC and distributors of
   BIND. Depending on your local processes, procedures, and expertise,
   you may wish to obtain updates from the ISC or from an operating
   system vendor who redistributes BIND.

Use Strong Cryptography to Authenticate Services

   Services and transactions that rely exclusively on the DNS system for
   authentication are inherently weak. We encourage organizations to use
   strong cryptography to authenicate services and transactions where
   possible. One common use of strong cryptography is the use of SSL in
   authenticating and encrypting electronic commerce transactions over
   the web. In addition to this use, we encourage organizations to use
   SSL, PGP, S/MIME, SSH, and other forms of strong cryptography to
   distribute executable content, secure electronic mail, distribute
   important information, and protect the confidentiality of all kinds of
   data traversing the Internet.

Use Split Horizon DNS to Minimize Impact

   It may also be possible to minimize the impact of the exploitation of
   these vulnerabilities by configuring your DNS environment to separate
   DNS servers used for the public dissemination of information about
   your hosts from the DNS servers used by your internal hosts to connect
   to other hosts on the Internet. Frequently, different security polices
   can be applied to these servers such that even if one server is
   compromised the other server will continue to function normally. Split
   horizon DNS configuration may also have other security benefits.

References

   To read more about the vulnerabilities described in this document,
   please visit the CERT/CC Vulnerability Notes Database:

   VU#196945 - ISC BIND 8 contains buffer overflow in transaction
          signature (TSIG) handling code
          http://www.kb.cert.org/vuls/id/196945

   VU#572183 - ISC BIND 4 contains buffer overflow in nslookupComplain()
          http://www.kb.cert.org/vuls/id/572183

   VU#868916 - ISC BIND 4 contains input validation error in
          nslookupComplain()
          http://www.kb.cert.org/vuls/id/868916

   VU#325431 - Queries to ISC BIND servers may disclose environment
          variables
          http://www.kb.cert.org/vuls/id/325431

   To cross-reference CERT/CC VU numbers with other vendor documents via
   CVE, please visit

   VU#196945 - ISC BIND 8 contains buffer overflow in transaction
          signature (TSIG) handling code
          http://cve.mitre.org/cgi-bin/cvename.cgi?name=CAN-2001-0010

   VU#572183 - ISC BIND 4 contains buffer overflow in nslookupComplain()
          http://cve.mitre.org/cgi-bin/cvename.cgi?name=CAN-2001-0011

   VU#868916 - ISC BIND 4 contains input validation error in
          nslookupComplain()
          http://cve.mitre.org/cgi-bin/cvename.cgi?name=CAN-2001-0013

   VU#325431 - Queries to ISC BIND servers may disclose environment
          variables
          http://cve.mitre.org/cgi-bin/cvename.cgi?name=CAN-2001-0012

   For information on historical issues involving BIND vulnerabilities
   and compromises, please visit

   CERT Advisory CA-2000-20 Multiple Denial-of-Service Problems in ISC
          BIND
          http://www.cert.org/advisories/CA-2000-20.html

   CERT Advisory CA-2000-03 Continuing Compromises of DNS servers
          http://www.cert.org/advisories/CA-2000-03.html

   CERT Advisory CA-1999-14 Multiple Vulnerabilities in BIND
          http://www.cert.org/advisories/CA-1999-14.html

   CERT Advisory CA-1998-05 Multiple Vulnerabilities in BIND
          http://www.cert.org/advisories/CA-1998-05.html

   CERT Advisory CA-1997-22 BIND - The Berkeley Internet Name Daemon
          http://www.cert.org/advisories/CA-1997-22.html

   CERT Summary CS-2000-02
          http://www.cert.org/summaries/CS-2000-02.html

   CERT Summary CS-2000-01
          http://www.cert.org/summaries/CS-2000-01.html

   CERT Summary CS-1999-04
          http://www.cert.org/summaries/CS-99-04.html

   CERT Summary CS-1998-07
          http://www.cert.org/summaries/CS-98.07.html

   CERT Summary CS-1998-06
          http://www.cert.org/summaries/CS-98.06.html

   CERT Summary CS-1998-05
          http://www.cert.org/summaries/CS-98.05.html

   CERT Summary CS-1998-04
          http://www.cert.org/summaries/CS-98.04.html

   For more information on transaction signatures, please visit

   RFC 2535: Domain Name System Security Extensions
          http://www.ietf.org/rfc/rfc2535.txt

   RFC 2845: Secret Key Transaction Authentication for DNS (TSIG)
          http://www.ietf.org/rfc/rfc2845.txt

Appendix A. - Vendor Information

   This appendix contains information provided by vendors for this
   advisory. When vendors report new information to the CERT/CC, we
   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.

Caldera Systems

   OpenLinux 2.3, eServer 2.3.1 and eDesktop 2.4 are all vulnerable.

   Update packages will be provided at

          ftp://ftp.calderasystems.com/pub/updates/OpenLinux/2.3
          ftp://ftp.calderasystems.com/pub/updates/OpenLinux/2.3
          ftp://ftp.calderasystems.com/pub/updates/eDesktop/2.4

Compaq Computer Corporation

COMPAQ COMPUTER CORPORATION
-------------------------------------------------------------------------------
-----
 VU#325431 INFOLEAK
-------------------------------------------------------------------------------
-----
 Compaq Tru64 UNIX V5.1 and V5.0 *evaluation incomplete
 Compaq Tru64 UNIX V4.0D/F/G *evaluation incomplete

-------------------------------------------------------------------------------
-----
 VU#572183 - buffer overflow in nslookupComplain()
 VU#868916 - input validation error in nslookupComplain()
-------------------------------------------------------------------------------
-----
 Compaq Tru64 UNIX V5.1 and V5.0 - Not Vulnerable
 Compaq Tru64 UNIX V4.0D/F/G - *evaluation incomplete.

-------------------------------------------------------------------------------
-----
 VU#196945 - BIND 8 contains buffer overflow in transaction signature handling
 code
-------------------------------------------------------------------------------
-----
 Compaq Tru64 UNIX V5.1 and V5.0 - *evaluation incomplete
 Compaq Tru64 UNIX V4.0D/F/G - Not Vulnerable

* At the time of writing this document, the problems identified are
currently still under evaluation by engineering. Compaq will provide
notice of the completion/availability of the patches through AES
services (DIA, DSNlink FLASH), the ** Security mailing list, and be
available from your normal Compaq Support channel.

**You may subscribe to the Security mailing list at:

http://www.support.compaq.com/patches/mailing-list.shtml

COMPAQ COMPUTER CORPORATION
-------------------------------------------------------------------------------
-----

FreeBSD, Inc.

   No supported version of FreeBSD contains BIND 4.x, so this does not
   affect us. We current ship betas of 8.2.3 in the FreeBSD 4.x release
   branch, and will be upgrading to 8.2.3 once it is released.

Hewlett-Packard Company

   None of the Bind versions of HP-UX is vulnerable to VU#196945 -
   problem of buffer overflow in TSIG handling code.

   HP's Bind 8.1.2 is vulnerable to VU#325183 (infoleak problem). Bind
   4.9.7 is vulnerable to both VU#572183 (infoleak problem) and VU#325183
   (nslookupComplain() buffer overflow).

   Fixes are in process.

IBM Corporation

   VU#325431 - Queries to ISC BIND servers may disclose environment
   variables

   IBM's AIX operating system may be vulnerable to this "inverse query"
   exploitation. We are working to understand the technical nature of
   this exploit; when done, we expect to verify AIX's vulnerability. We
   will provide updates to this page as we progress [in] studying this
   exploit.

   VU#572183 - ISC BIND 4 contains buffer overflow in nslookupComplain()

   IBM's AIX operating system is vulnerable to this potential exploit in
   named4. We are working to fix this quickly and we intend to post an
   emergency fix ASAP.

   VU#868916 - ISC BIND 4 contains input validation error in
   nslookupComplain()

   IBM's AIX operating system is vulnerable to this potential exploit,
   and is working quickly toward a fix.

Sun Microsystems, Inc.

   Solaris(tm) versions 2.4, 2.5, 2.5.1 and 2.6 contain revisions of BIND
   4

   Solaris(tm) versions 7 and 8 contain BIND 8.1.2

   Sun is working to address the issues in VU#868916, VU#572183 and
   VU#325431 and will be issuing a Sun Security Bulletin when further
   information is available.

   VU#196945 is not present in currently supported versions of Solaris.
     _________________________________________________________________

   The CERT/CC thanks the COVERT Labs at PGP Security for discovering and
   analyzing three of these vulnerabilities (VU#196945, VU#572183, and
   VU#868916) and Claudio Musmarra for discovering the infoleak
   vulnerability (VU#325431). We also thank the Internet Software
   Consortium for providing patches to fix the vulnerabilities.
     _________________________________________________________________

   This document was written by Jeffrey P. Lanza, Cory Cohen, Ian Finlay,
   and Shawn Hernan.
   ______________________________________________________________________

   This document is available from:
   http://www.cert.org/advisories/CA-2001-02.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
   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 2001 Carnegie Mellon University.

   Revision History
January 29, 2001: Initial release
-- End of PGP signed section, PGP failed!

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