88399 2003-01-21 00:20 /8 rader/ Dave Ahmad <da@securityfocus.com>
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88400 2003-01-21 00:20 /336 rader/ Dave Ahmad <da@securityfocus.com>
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Wed, 15 Jan 2003 15:54:42 -0500 Date: Wed, 15 Jan 2003
15:54:42 -0500 Message-Id: <CA-2003-01.1@cert.org> From: CERT
Advisory <cert-advisory@cert.org> To: cert-advisory@cert.org
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<http://www.cert.org/> Subject: CERT Advisory CA-2003-01 Buffer
Overflows in ISC DHCPD Minires Library Precedence: bulk
-----BEGIN PGP SIGNED MESSAGE-----
CERT Advisory CA-2003-01 Buffer Overflows in ISC DHCPD Minires Library
Original release date: January 15, 2003
Last revised: --
Source: CERT/CC
A complete revision history can be found at the end of this file.
Systems Affected
* Systems running ISC DHCPD versions 3.0 through 3.0.1RC10,
inclusive.
* For detailed vendor status information, see
http://www.kb.cert.org/vuls/id/284857#systems
Overview
The Internet Software Consortium (ISC) has discovered several
buffer overflow vulnerabilities in their implementation of DHCP
(ISC DHCPD). These vulnerabilities may allow remote attackers to
execute arbitrary code on affected systems. At this time, we are
not aware of any exploits.
I. Description
There are multiple remote buffer overflow vulnerabilities in the
ISC implementation of DHCP. As described in RFC 2131, "the
Dynamic Host Configuration Protocol (DHCP) provides a framework
for passing configuration information to hosts on a TCP/IP
network." In addition to supplying hosts with network
configuration data, ISC DHCPD allows the DHCP server to
dynamically update a DNS server, eliminating the need for manual
updates to the name server configuration. Support for dynamic DNS
updates is provided by the NSUPDATE feature.
During an internal source code audit, developers from the ISC
discovered several vulnerabilities in the error handling routines
of the minires library, which is used by NSUPDATE to resolve
hostnames. These vulnerabilities are stack-based buffer overflows
that may be exploitable by sending a DHCP message containing a
large hostname value. Note: Although the minires library is
derived from the BIND 8 resolver library, these vulnerabilities do
not affect any current versions of BIND.
The CERT/CC is tracking this issue as VU#284857. This reference
number corresponds to CVE candidate CAN-2003-0026.
II. Impact
Remote attackers may be able to execute arbitrary code with the
privileges of the user running ISC DHCPD.
III. Solution
Upgrade or apply a patch
The ISC has addressed these vulnerabilities in versions 3.0pl2 and
3.0.1RC11 of ISC DHCPD. If your software vendor supplies ISC DHCPD
as part of an operating system distribution, please see Appendix A
for vendor-specific patch information.
For a detailed list of vendors that have been notified of this
issue by the CERT/CC, please see
http://www.kb.cert.org/vuls/id/284857#systems
Disable dynamic DNS updates (NSUPDATE)
As an interim measure, the ISC recommends disabling the NSUPDATE
feature on affected DHCP servers.
Block external access to DHCP server ports
As an interim measure, it is possible to limit exposure to these
vulnerabilities by restricting external access to affected DHCP
servers on the following ports:
bootps 67/tcp # Bootstrap Protocol Server
bootps 67/udp # Bootstrap Protocol Server
bootpc 68/tcp # Bootstrap Protocol Client
bootpc 68/udp # Bootstrap Protocol Client
Disable the DHCP service
As a general rule, the CERT/CC recommends disabling any service or
capability that is not explicitly required. Depending on your
network configuration, you may not need to use DHCP.
Appendix A. - Vendor Information
This appendix contains information provided by vendors for this
advisory. As vendors report new information to the CERT/CC, we
will 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.
Apple Computer, Inc.
Mac OS X and Mac OS X Server do not contain the vulnerability
described in this notice.
Berkeley Software Design, Inc. (BSDI)
This vulnerability is addressed by the M431-001 and M500-004
patches for the 4.3.1 and 5.0 versions of BSD/OS.
Cisco Systems
No Cisco products have been found to be affected by this
vulnerability.
Several Cisco products do utilize the ISC DHCPD, however, no Cisco
products implement the ISC DHCPD NSUPDATE feature, nor do they
include the minires library.
Cray Inc.
Cray Inc. is not vulnerable as dhcpd is not supported on any of
its products.
Fujitsu
Fujitsu's UXP/V OS is not vulnerable because it does not support
the ISC DHCPD.
Hewlett-Packard Company
Source: Hewlett-Packard Company
Software Security Response Team
cross reference id: SSRT2423
HP-UX - not vulnerable
HP-MPE/ix - not vulnerable
HP Tru64 UNIX - not vulnerable
HP OpenVMS - not vulnerable
HP NonStop Servers - not vulnerable
To report potential security vulnerabilities in HP software,
send an E-mail message to: mailto:security-alert@hp.com
Hitachi, Ltd.
We've checked up on our router (Hitachi,Ltd. GR2000 series) about
[VU#284857]. Our DHCP implementation is NOT vulnerable.
IBM Corporation
IBM's AIX does not ship with the ISC DHCP daemon. The issues
discussed in VU#284857 or any following advisories based on this
vulnerability note do not pertain to AIX.
Internet Software Consortium
We have a patched version of 3.0 available (3.0pl2) and a new
release candidate for the next bug-fix release (3.0.1RC11). Both
of these new releases are available from
http://www.isc.org/products/DHCP/.
MontaVista Software
None of MontaVista Software's Linux products are vulnerable to this
issue.
NEC Inc.
[Server Products]
* EWS/UP 48 Series operating system
- is NOT vulnerable.
NetBSD
Currently supported versions of NetBSD do not contain the error
handling routine vulnerabilities. Such vulnerabilities were fixed
prior to the release of NetBSD 1.5.
With respect to the patch to ns_name.c, we believe that this is
good defensive programming and have applied the patch to
NetBSD-current. However, all calls to ns_name_ntol in the NetBSD
source base pass a correct, constant, non-zero value as the datsiz
parameter.
Therefore, NetBSD is not vulnerable.
NetScreen
NetScreen is not vulnerable to this issue.
OpenBSD
OpenBSD's dhcp support is much modified, does not have that
feature, and therefore does not have that bug.
Openwall GNU/*/Linux
Openwall GNU/*/Linux is not vulnerable. We don't yet provide a DHCP
suite.
Red Hat Inc.
Red Hat distributes a vulnerable version of ISC DHCP in Red Hat
Linux 8.0. Other distributions of Red Hat Linux are not
vulnerable to these issues. New DHCP packages are available along
with our advisory at the URL below. Users of the Red Hat Network
can update their systems using the 'up2date' tool.
http://rhn.redhat.com/errata/RHSA-2003-011.html
Riverstone Networks
Riverstone Networks is not vulnerable to VU#284857.
Sun Microsystems, Inc.
Sun confirms that we are not vulnerable to the issues described in
VU#284857. Solaris does not ship the ISC DHCPD and does not use
any of the ISC DHCPD source in its version of DHCPD.
SuSE Linux AG
We are preparing updates, that will be released soon.
Xerox
Xerox is aware of this vulnerability and is currently assessing all
products. This statement will be updated as new information becomes
available.
_________________________________________________________________
The CERT Coordination Center thanks David Hankins of the Internet
Software Consortium for notifying us about this problem and for
helping us to construct this document. We also thank Jacques A.
Vidrine for drawing attention to this issue.
_________________________________________________________________
Author: This document was written by Jeffrey P. Lanza.
______________________________________________________________________
This document is available from:
http://www.cert.org/advisories/CA-2003-01.html
______________________________________________________________________
CERT/CC Contact Information
Email: cert@cert.org
Phone: +1 412-268-7090 (24-hour hotline)
Fax: +1 412-268-6989
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______________________________________________________________________
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Any material furnished by Carnegie Mellon University and the Software
Engineering Institute is furnished on an "as is" basis. Carnegie
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Revision History
January 15, 2003: Initial release
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(88400) /Dave Ahmad <da@securityfocus.com>/(Ombruten)