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[lugbe] Fwd: Re: [luga] Achtung, neuer bind bug --> WG: CERT Advisory CA-2001-02
zur Info
Roger
Betreff: [lugbe] Fwd: Re: [luga] Achtung, neuer bind bug
hallo lugbe
kennt den schon jemand?
was ist davon zu halten?
-----Ursprüngliche Nachricht-----
Von: CERT Advisory [SMTP:cert-advisory at cert.org]
<[SMTP:cert-advisory at cert.org]>
Gesendet am: Montag, 29. Januar 2001 15:18
An: cert-advisory at cert.org <cert-advisory at cert.org>
Betreff: CERT Advisory CA-2001-02
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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
<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
<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/ <ftp://ftp.isc.org/isc/bind/src/>
The BIND 9.1 distribution can be downloaded from
ftp://ftp.isc.org/isc/bind9/ <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
<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
<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
<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
<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
<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
<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
<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
<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
<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
<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
<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
<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
<http://www.cert.org/advisories/CA-1997-22.html>
CERT Summary CS-2000-02
http://www.cert.org/summaries/CS-2000-02.html
<http://www.cert.org/summaries/CS-2000-02.html>
CERT Summary CS-2000-01
http://www.cert.org/summaries/CS-2000-01.html
<http://www.cert.org/summaries/CS-2000-01.html>
CERT Summary CS-1999-04
http://www.cert.org/summaries/CS-99-04.html
<http://www.cert.org/summaries/CS-99-04.html>
CERT Summary CS-1998-07
http://www.cert.org/summaries/CS-98.07.html
<http://www.cert.org/summaries/CS-98.07.html>
CERT Summary CS-1998-06
http://www.cert.org/summaries/CS-98.06.html
<http://www.cert.org/summaries/CS-98.06.html>
CERT Summary CS-1998-05
http://www.cert.org/summaries/CS-98.05.html
<http://www.cert.org/summaries/CS-98.05.html>
CERT Summary CS-1998-04
http://www.cert.org/summaries/CS-98.04.html
<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 <http://www.ietf.org/rfc/rfc2535.txt>
RFC 2845: Secret Key Transaction Authentication for DNS (TSIG)
http://www.ietf.org/rfc/rfc2845.txt <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/OpenLinux/2.3
<ftp://ftp.calderasystems.com/pub/updates/OpenLinux/2.3>
ftp://ftp.calderasystems.com/pub/updates/eDesktop/2.4
<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
<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
<http://www.cert.org/advisories/CA-2001-02.html>
______________________________________________________________________
CERT/CC Contact Information
Email: cert at cert.org <cert at 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 <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/ <http://www.cert.org/>
To subscribe to the CERT mailing list for advisories and bulletins,
send email to majordomo at cert.org <majordomo at 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
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