Protect yourself against future threats.
-----BEGIN PGP SIGNED MESSAGE----- Hash: SHA1 =========================================================================== AUSCERT External Security Bulletin Redistribution ESB-2008.0855 -- [FreeBSD] Remote kernel panics on IPv6 connections 9 September 2008 =========================================================================== AusCERT Security Bulletin Summary --------------------------------- Product: icmp6 Publisher: FreeBSD Operating System: FreeBSD Impact: Denial of Service Access: Remote/Unauthenticated CVE Names: CVE-2008-3530 Original Bulletin: http://www.vuxml.org/freebsd/2f794295-7b69-11dd-80ba-000bcdf0a03b.html Revision History: September 9 2008: Updated Original Bulletin URL September 4 2008: Initial Release - --------------------------BEGIN INCLUDED TEXT-------------------- - -----BEGIN PGP SIGNED MESSAGE----- Hash: SHA1 ============================================================================= FreeBSD-SA-08:09.icmp6 Security Advisory The FreeBSD Project Topic: Remote kernel panics on IPv6 connections Category: core Module: sys_netinet6 Announced: 2008-09-03 Credits: Tom Parker, Bjoern A. Zeeb Affects: All supported versions of FreeBSD. Corrected: 2008-09-03 19:09:47 UTC (RELENG_7, 7.1-PRERELEASE) 2008-09-03 19:09:47 UTC (RELENG_7_0, 7.0-RELEASE-p4) 2008-09-03 19:09:47 UTC (RELENG_6, 6.4-PRERELEASE) 2008-09-03 19:09:47 UTC (RELENG_6_3, 6.3-RELEASE-p4) CVE Name: CVE-2008-3530 For general information regarding FreeBSD Security Advisories, including descriptions of the fields above, security branches, and the following sections, please visit <URL:http://security.FreeBSD.org/>. I. Background IPv6 nodes use ICMPv6 amongst other things to report errors encountered while processing packets. The 'Packet Too Big Message' is sent in case a node cannot forward a packet because the size of the packet is larger than the MTU of next-hop link. II. Problem Description In case of an incoming ICMPv6 'Packet Too Big Message', there is an insufficient check on the proposed new MTU for a path to the destination. III. Impact When the kernel is configured to process IPv6 packets and has active IPv6 TCP sockets, a specifically crafted ICMPv6 'Packet Too Big Message' could cause the TCP stack of the kernel to panic, IV. Workaround Systems without INET6 / IPv6 support are not vulnerable and neither are systems which do not listen on any IPv6 TCP sockets and have no active IPv6 connections. Filter ICMPv6 'Packet Too Big Messages' using a firewall, but this will at the same time break PMTU support for IPv6 connections. V. Solution Perform one of the following: 1) Upgrade your vulnerable system to 6-STABLE or 7-STABLE, or to the RELENG_6_3 or RELENG_7_0 security branch dated after the correction date. 2) To patch your present system: The following patches have been verified to apply to FreeBSD 6.3 and FreeBSD 7.0 systems. a) Download the relevant patch from the location below, and verify the detached PGP signature using your PGP utility. # fetch http://security.FreeBSD.org/patches/SA-08:09/icmp6.patch # fetch http://security.FreeBSD.org/patches/SA-08:09/icmp6.patch.asc b) Apply the patch. # cd /usr/src # patch < /path/to/patch c) Recompile your kernel as described in <URL:http://www.FreeBSD.org/handbook/kernelconfig.html> and reboot the system. VI. Correction details The following list contains the revision numbers of each file that was corrected in FreeBSD. Branch Revision Path - - ------------------------------------------------------------------------- RELENG_6 src/sys/netinet6/icmp6.c 1.62.2.11 RELENG_6_3 src/UPDATING 1.416.2.37.2.9 src/sys/conf/newvers.sh 1.69.2.15.2.8 src/sys/netinet6/icmp6.c 1.62.2.9.2.1 RELENG_7 src/sys/netinet6/icmp6.c 1.80.2.7 RELENG_7_0 src/UPDATING 1.507.2.3.2.8 src/sys/conf/newvers.sh 1.72.2.5.2.8 src/sys/netinet6/icmp6.c 1.80.4.1 - - ------------------------------------------------------------------------- VII. References http://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2008-3530 The latest revision of this advisory is available at http://security.FreeBSD.org/advisories/FreeBSD-SA-08:09.icmp6.asc - -----BEGIN PGP SIGNATURE----- Version: GnuPG v1.4.9 (FreeBSD) iD8DBQFIvu2hFdaIBMps37IRAjxxAJwIIXP+ALAZkvG5m687PC+92BtXTwCfUZdS AvvrO0r+UAa6bn1H9mFf9So= =MBB1 - -----END PGP SIGNATURE----- - --------------------------END INCLUDED TEXT-------------------- You have received this e-mail bulletin as a result of your organisation's registration with AusCERT. The mailing list you are subscribed to is maintained within your organisation, so if you do not wish to continue receiving these bulletins you should contact your local IT manager. If you do not know who that is, please send an email to auscert@auscert.org.au and we will forward your request to the appropriate person. NOTE: Third Party Rights 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 follow or act on information or advice contained in this security bulletin is the responsibility of each user or organisation, and should be considered in accordance with your organisation's site policies and procedures. AusCERT takes no responsibility for consequences which may arise from following or acting on information or advice contained in this security bulletin. NOTE: This is only the original release of the security bulletin. It may 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 author's website 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/render.html?cid=1980 If you believe that your computer system has been compromised or attacked in any way, we encourage you to let us know by completing the secure National IT Incident Reporting Form at: http://www.auscert.org.au/render.html?it=3192 =========================================================================== Australian Computer Emergency Response Team The University of Queensland Brisbane Qld 4072 Internet Email: auscert@auscert.org.au 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). On call after hours for member emergencies only. =========================================================================== -----BEGIN PGP SIGNATURE----- Comment: http://www.auscert.org.au/render.html?it=1967 iQCVAwUBSMYSICh9+71yA2DNAQInpgQAhyxrKPF/rJf36uqcT/n52D0aaiOZu8aw X1AiHm6uZIyNiPvs2EYFfUJGoWv2ON0KaYZGu24hAWYcMG8cUBrYdvcpe/YCJj4t MX9ZALfQ4mBzZSaDxWij0uVg3siJU684uQf/v/M8I7xu1vsobsYm7MimXbe58Kb2 Hj4gS7desC0= =AB3o -----END PGP SIGNATURE-----