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<P>Got this from CERT. ISC DHCPD is vulnerable. There are only 2 "popular"
distros that are affect that we talk about here. (something is just not right
with that sentence). Anyway, It appears that RHL 8.0 (not other versions) and
SUSE are affected (NOT Mandrake).</P>
<P>HTH</P>
<P>-----BEGIN PGP SIGNED MESSAGE-----</P>
<P>CERT Advisory CA-2003-01 Buffer Overflows in ISC DHCPD Minires Library</P>
<P>Original release date: January 15, 2003</P>
<P>Last revised: --</P>
<P>Source: CERT/CC</P>
<P>A complete revision history can be found at the end of this file.</P>
<P>Systems Affected</P>
<P>* Systems running ISC DHCPD versions 3.0 through 3.0.1RC10,</P>
<P>inclusive.</P>
<P>* For detailed vendor status information, see</P>
<P></FONT><A href="http://www.kb.cert.org/vuls/id/284857"><U><FONT color=#0000ff
size=2>http://www.kb.cert.org/vuls/id/284857#systems</U></FONT></A></P><FONT
size=2>
<P>Overview</P>
<P>The Internet Software Consortium (ISC) has discovered several buffer</P>
<P>overflow vulnerabilities in their implementation of DHCP (ISC DHCPD).</P>
<P>These vulnerabilities may allow remote attackers to execute arbitrary</P>
<P>code on affected systems. At this time, we are not aware of any</P>
<P>exploits.</P>
<P>I. Description</P>
<P>There are multiple remote buffer overflow vulnerabilities in the ISC</P>
<P>implementation of DHCP. As described in RFC 2131, "the Dynamic Host</P>
<P>Configuration Protocol (DHCP) provides a framework for passing</P>
<P>configuration information to hosts on a TCP/IP network." In addition to</P>
<P>supplying hosts with network configuration data, ISC DHCPD allows the</P>
<P>DHCP server to dynamically update a DNS server, eliminating the need</P>
<P>for manual updates to the name server configuration. Support for</P>
<P>dynamic DNS updates is provided by the NSUPDATE feature.</P>
<P>During an internal source code audit, developers from the ISC</P>
<P>discovered several vulnerabilities in the error handling routines of</P>
<P>the minires library, which is used by NSUPDATE to resolve hostnames.</P>
<P>These vulnerabilities are stack-based buffer overflows that may be</P>
<P>exploitable by sending a DHCP message containing a large hostname</P>
<P>value. Note: Although the minires library is derived from the BIND 8</P>
<P>resolver library, these vulnerabilities do not affect any current</P>
<P>versions of BIND.</P>
<P>The CERT/CC is tracking this issue as VU#284857. This reference number</P>
<P>corresponds to CVE candidate CAN-2003-0026.</P>
<P>II. Impact</P>
<P>Remote attackers may be able to execute arbitrary code with the</P>
<P>privileges of the user running ISC DHCPD.</P>
<P>III. Solution</P>
<P>Upgrade or apply a patch</P>
<P>The ISC has addressed these vulnerabilities in versions 3.0pl2 and</P>
<P>3.0.1RC11 of ISC DHCPD. If your software vendor supplies ISC DHCPD as</P>
<P>part of an operating system distribution, please see Appendix A for</P>
<P>vendor-specific patch information.</P>
<P>For a detailed list of vendors that have been notified of this issue by</P>
<P>the CERT/CC, please see</P>
<P></FONT><A href="http://www.kb.cert.org/vuls/id/284857"><U><FONT color=#0000ff
size=2>http://www.kb.cert.org/vuls/id/284857#systems</U></FONT></A></P><FONT
size=2>
<P>Disable dynamic DNS updates (NSUPDATE)</P>
<P>As an interim measure, the ISC recommends disabling the NSUPDATE</P>
<P>feature on affected DHCP servers.</P>
<P>Block external access to DHCP server ports</P>
<P>As an interim measure, it is possible to limit exposure to these</P>
<P>vulnerabilities by restricting external access to affected DHCP servers</P>
<P>on the following ports:</P>
<P>bootps 67/tcp # Bootstrap Protocol Server</P>
<P>bootps 67/udp # Bootstrap Protocol Server</P>
<P>bootpc 68/tcp # Bootstrap Protocol Client</P>
<P>bootpc 68/udp # Bootstrap Protocol Client</P>
<P>Disable the DHCP service</P>
<P>As a general rule, the CERT/CC recommends disabling any service or</P>
<P>capability that is not explicitly required. Depending on your network</P>
<P>configuration, you may not need to use DHCP.</P>
<P>Appendix A. - Vendor Information</P>
<P>This appendix contains information provided by vendors for this</P>
<P>advisory. As vendors report new information to the CERT/CC, we will</P>
<P>update this section and note the changes in our revision history. If a</P>
<P>particular vendor is not listed below, we have not received their</P>
<P>comments.</P>
<P>Apple Computer, Inc.</P>
<P>Mac OS X and Mac OS X Server do not contain the vulnerability described</P>
<P>in this notice.</P>
<P>Berkeley Software Design, Inc. (BSDI)</P>
<P>This vulnerability is addressed by the M431-001 and M500-004 patches</P>
<P>for the 4.3.1 and 5.0 versions of BSD/OS.</P>
<P>Cisco Systems</P>
<P>No Cisco products have been found to be affected by this vulnerability.</P>
<P>Several Cisco products do utilize the ISC DHCPD, however, no Cisco</P>
<P>products implement the ISC DHCPD NSUPDATE feature, nor do they include</P>
<P>the minires library.</P>
<P>Cray Inc.</P>
<P>Cray Inc. is not vulnerable as dhcpd is not supported on any of its</P>
<P>products.</P>
<P>Fujitsu</P>
<P>Fujitsu's UXP/V OS is not vulnerable because it does not support the</P>
<P>ISC DHCPD.</P>
<P>Hewlett-Packard Company</P>
<P>Source: Hewlett-Packard Company</P>
<P>Software Security Response Team</P>
<P></P>
<P></P>
<P>cross reference id: SSRT2423</P>
<P></P>
<P>HP-UX - not vulnerable</P>
<P>HP-MPE/ix - not vulnerable</P>
<P>HP Tru64 UNIX - not vulnerable</P>
<P>HP OpenVMS - not vulnerable</P>
<P>HP NonStop Servers - not vulnerable</P>
<P></P>
<P>To report potential security vulnerabilities in HP software,</P>
<P>send an E-mail message to: </FONT><A
href="mailto:security-alert@hp.com"><U><FONT color=#0000ff
size=2>mailto:security-alert@hp.com</U></FONT></A></P><FONT size=2>
<P>Hitachi, Ltd.</P>
<P>We've checked up on our router (Hitachi,Ltd. GR2000 series) about</P>
<P>[VU#284857]. Our DHCP implementation is NOT vulnerable.</P>
<P>IBM Corporation</P>
<P>IBM's AIX does not ship with the ISC DHCP daemon. The issues discussed</P>
<P>in VU#284857 or any following advisories based on this vulnerability</P>
<P>note do not pertain to AIX.</P>
<P>Internet Software Consortium</P>
<P>We have a patched version of 3.0 available (3.0pl2) and a new release</P>
<P>candidate for the next bug-fix release (3.0.1RC11). Both of these new</P>
<P>releases are available from </FONT><A
href="http://www.isc.org/products/DHCP/"><U><FONT color=#0000ff
size=2>http://www.isc.org/products/DHCP/</U></FONT></A><FONT size=2>.</P>
<P>MontaVista Software</P>
<P>None of MontaVista Software's Linux products are vulnerable to this</P>
<P>issue.</P>
<P>NEC Inc.</P>
<P>[Server Products]</P>
<P></P>
<P>* EWS/UP 48 Series operating system</P>
<P>- is NOT vulnerable.</P>
<P>NetBSD</P>
<P>Currently supported versions of NetBSD do not contain the error</P>
<P>handling routine vulnerabilities. Such vulnerabilities were fixed</P>
<P>prior to the release of NetBSD 1.5.</P>
<P>With respect to the patch to ns_name.c, we believe that this is good</P>
<P>defensive programming and have applied the patch to NetBSD-current.</P>
<P>However, all calls to ns_name_ntol in the NetBSD source base pass a</P>
<P>correct, constant, non-zero value as the datsiz parameter.</P>
<P>Therefore, NetBSD is not vulnerable.</P>
<P>NetScreen</P>
<P>NetScreen is not vulnerable to this issue.</P>
<P>OpenBSD</P>
<P>OpenBSD's dhcp support is much modified, does not have that feature,</P>
<P>and therefore does not have that bug.</P>
<P>Openwall GNU/*/Linux</P>
<P>Openwall GNU/*/Linux is not vulnerable. We don't yet provide a DHCP</P>
<P>suite.</P>
<P>Red Hat Inc.</P>
<P>Red Hat distributes a vulnerable version of ISC DHCP in Red Hat Linux</P>
<P>8.0. Other distributions of Red Hat Linux are not vulnerable to these</P>
<P>issues. New DHCP packages are available along with our advisory at the</P>
<P>URL below. Users of the Red Hat Network can update their systems using</P>
<P>the 'up2date' tool.</P>
<P></FONT><A href="http://rhn.redhat.com/errata/RHSA-2003-011.html"><U><FONT
color=#0000ff
size=2>http://rhn.redhat.com/errata/RHSA-2003-011.html</U></FONT></A></P><FONT
size=2>
<P>Riverstone Networks</P>
<P>Riverstone Networks is not vulnerable to VU#284857.</P>
<P>Sun Microsystems, Inc.</P>
<P>Sun confirms that we are not vulnerable to the issues described in</P>
<P>VU#284857. Solaris does not ship the ISC DHCPD and does not use any of</P>
<P>the ISC DHCPD source in its version of DHCPD.</P>
<P>SuSE Linux AG</P>
<P>We are preparing updates, that will be released soon.</P>
<P>Xerox</P>
<P>Xerox is aware of this vulnerability and is currently assessing all</P>
<P>products. This statement will be updated as new information becomes</P>
<P>available.</P>
<P>_________________________________________________________________</P>
<P>The CERT Coordination Center thanks David Hankins of the Internet</P>
<P>Software Consortium for notifying us about this problem and for helping</P>
<P>us to construct this document. We also thank Jacques A. Vidrine for</P>
<P>drawing attention to this issue.</P>
<P>_________________________________________________________________</P>
<P>Author: This document was written by Jeffrey P. Lanza.</P>
<P>______________________________________________________________________</P>
<P>This document is available from:</P>
<P></FONT><A href="http://www.cert.org/advisories/CA-2003-01.html"><U><FONT
color=#0000ff
size=2>http://www.cert.org/advisories/CA-2003-01.html</U></FONT></A></P><FONT
size=2>
<P>______________________________________________________________________</P>
<P>CERT/CC Contact Information</P>
<P>Email: cert@cert.org</P>
<P>Phone: +1 412-268-7090 (24-hour hotline)</P>
<P>Fax: +1 412-268-6989</P>
<P>Postal address:</P>
<P>CERT Coordination Center</P>
<P>Software Engineering Institute</P>
<P>Carnegie Mellon University</P>
<P>Pittsburgh PA 15213-3890</P>
<P>U.S.A.</P>
<P>CERT/CC personnel answer the hotline 08:00-17:00 EST(GMT-5) /</P>
<P>EDT(GMT-4) Monday through Friday; they are on call for emergencies</P>
<P>during other hours, on U.S. holidays, and on weekends.</P>
<P>Using encryption</P>
<P>We strongly urge you to encrypt sensitive information sent by email.</P>
<P>Our public PGP key is available from</P>
<P></FONT><A href="http://www.cert.org/CERT_PGP.key"><U><FONT color=#0000ff
size=2>http://www.cert.org/CERT_PGP.key</U></FONT></A></P><FONT size=2>
<P>If you prefer to use DES, please call the CERT hotline for more</P>
<P>information.</P>
<P>Getting security information</P>
<P>CERT publications and other security information are available from</P>
<P>our web site</P>
<P></FONT><A href="http://www.cert.org/"><U><FONT color=#0000ff
size=2>http://www.cert.org/</U></FONT></A></P><FONT size=2>
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<P>Copyright 2003 Carnegie Mellon University.</P>
<P>Revision History</P>
<P>January 15, 2003: Initial release</P>
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