[FreeBSD-Announce] FreeBSD Security Advisory FreeBSD-SA-07:03.ipv6

27/04/07, [FreeBSD-Announce] FreeBSD Security Advisory FreeBSD-SA-07:03.ipv6
From: FreeBSD Security Advisories <security-advisories@freebsd.org>

Generated by MHonArc

CSIM Logo WelcomeCourses
Faculty, Student, Staff
Projects and reports
Conferences, workshop and seminars
Laboratories and reasearch facilities
Information related to CSIM
Information non-related to CSIM
Address, map, phone, etc.
Search

[Date Prev] [Date Next] [Thread Prev] [Thread Next] [Date Index] [Thread Index]


To: FreeBSD Security Advisories <security-advisories@freebsd.org>
Subject: [FreeBSD-Announce] FreeBSD Security Advisory FreeBSD-SA-07:03.ipv6
From: FreeBSD Security Advisories <security-advisories@freebsd.org>
Date: Thu, 26 Apr 2007 23:49:47 GMT
Cc:
Delivered-to: freebsd-announce@freebsd.org
List-archive: <http://lists.freebsd.org/pipermail/freebsd-announce>
List-help: <mailto:freebsd-announce-request@freebsd.org?subject=help>
List-id: "Project Announcements \[moderated\]" <freebsd-announce.freebsd.org>
List-post: <mailto:freebsd-announce@freebsd.org>
List-subscribe: <http://lists.freebsd.org/mailman/listinfo/freebsd-announce>, <mailto:freebsd-announce-request@freebsd.org?subject=subscribe>
List-unsubscribe: <http://lists.freebsd.org/mailman/listinfo/freebsd-announce>, <mailto:freebsd-announce-request@freebsd.org?subject=unsubscribe>
Reply-to: freebsd-security@freebsd.org
Sender: owner-freebsd-announce@freebsd.org

-----BEGIN PGP SIGNED MESSAGE-----
Hash: SHA1

=============================================================================
FreeBSD-SA-07:03.ipv6                                       Security Advisory
                                                          The FreeBSD Project

Topic:          IPv6 Routing Header 0 is dangerous

Category:       core
Module:         ipv6
Announced:      2007-04-26
Credits:        Philippe Biondi, Arnaud Ebalard, Jun-ichiro itojun Hagino
Affects:        All FreeBSD releases.
Corrected:      2007-04-24 11:42:42 UTC (RELENG_6, 6.2-STABLE)
                2007-04-26 23:42:23 UTC (RELENG_6_2, 6.2-RELEASE-p4)
                2007-04-26 23:41:59 UTC (RELENG_6_1, 6.1-RELEASE-p16)
                2007-04-24 11:44:23 UTC (RELENG_5, 5.5-STABLE)
                2007-04-26 23:41:27 UTC (RELENG_5_5, 5.5-RELEASE-p12)
CVE Name:       CVE-2007-2242

I.   Background

IPv6 provides a routing header option which allows a packet sender to
indicate how the packet should be routed, overriding the routing knowledge
present in a network.  This functionality is roughly equivalent to the
"source routing" option in IPv4.  All nodes in an IPv6 network -- both
routers and hosts -- are required by RFC 2640 to process such headers.

II.  Problem Description

There is no mechanism for preventing IPv6 routing headers from being used
to route packets over the same link(s) many times.

III. Impact

An attacker can "amplify" a denial of service attack against a link between
two vulnerable hosts; that is, by sending a small volume of traffic the
attacker can consume a much larger amount of bandwidth between the two
vulnerable hosts.

An attacker can use vulnerable hosts to "concentrate" a denial of service
attack against a victim host or network; that is, a set of packets sent
over a period of 30 seconds or more could be constructed such that they
all arrive at the victim within a period of 1 second or less.

Other attacks may also be possible.

IV.  Workaround

No workaround is available.

V.   Solution

NOTE WELL: The solution described below causes IPv6 type 0 routing headers
to be ignored.  Support for IPv6 type 0 routing headers can be re-enabled
if required by setting the newly added net.inet6.ip6.rthdr0_allowed sysctl
to a non-zero value.

Perform one of the following:

1) Upgrade your vulnerable system to 5-STABLE, or 6-STABLE, or to the
RELENG_6_2, RELENG_6_1, or RELENG_5_5 security branch dated after the
correction date.

2) To patch your present system:

The following patches have been verified to apply to FreeBSD 5.5, 6.1,
and 6.2 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-07:03/ipv6.patch
# fetch http://security.FreeBSD.org/patches/SA-07:03/ipv6.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_5
  src/sys/netinet6/in6.h                                         1.35.2.5
  src/sys/netinet6/in6_proto.c                                   1.29.2.5
  src/sys/netinet6/route6.c                                      1.10.4.2
RELENG_5_5
  src/UPDATING                                            1.342.2.35.2.12
  src/sys/conf/newvers.sh                                  1.62.2.21.2.14
  src/sys/netinet6/in6.h                                     1.35.2.3.2.1
  src/sys/netinet6/in6_proto.c                               1.29.2.4.2.1
  src/sys/netinet6/route6.c                                  1.10.4.1.4.1
RELENG_6
  src/sys/netinet6/in6.h                                         1.36.2.8
  src/sys/netinet6/in6_proto.c                                   1.32.2.6
  src/sys/netinet6/route6.c                                      1.11.2.2
RELENG_6_2
  src/UPDATING                                             1.416.2.29.2.7
  src/sys/conf/newvers.sh                                   1.69.2.13.2.7
  src/sys/netinet6/in6.h                                     1.36.2.7.2.1
  src/sys/netinet6/in6_proto.c                               1.32.2.5.2.1
  src/sys/netinet6/route6.c                                  1.11.2.1.4.1
RELENG_6_1
  src/UPDATING                                            1.416.2.22.2.18
  src/sys/conf/newvers.sh                                  1.69.2.11.2.18
  src/sys/netinet6/in6.h                                     1.36.2.6.2.1
  src/sys/netinet6/in6_proto.c                               1.32.2.4.2.1
  src/sys/netinet6/route6.c                                  1.11.2.1.2.1
- -------------------------------------------------------------------------

VII. References

http://www.secdev.org/conf/IPv6_RH_security-csw07.pdf

http://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2007-2242

The latest revision of this advisory is available at
http://security.FreeBSD.org/advisories/FreeBSD-SA-07:03.ipv6.asc
-----BEGIN PGP SIGNATURE-----
Version: GnuPG v1.4.6 (FreeBSD)

iD4DBQFGMTlvFdaIBMps37IRApu3AJYsifWIDLcyxNcMdnkvw4nBqXFoAJ43+IzB
M5sIdCmLQABByFlbMB2BjQ==
=OrNf
-----END PGP SIGNATURE-----
_______________________________________________
freebsd-announce@freebsd.org mailing list
http://lists.freebsd.org/mailman/listinfo/freebsd-announce
To unsubscribe, send any mail to "freebsd-announce-unsubscribe@freebsd.org"

Previous message sorted by date: FreeBSD Security Advisory FreeBSD-SA-07:02.bind
Next message sorted by date: [FreeBSD-Announce] FreeBSD Security Advisory FreeBSD-SA-07:04.file
Previous message sorted by thread: FreeBSD Security Advisory FreeBSD-SA-07:02.bind
Next message by thread: [FreeBSD-Announce] FreeBSD Security Advisory FreeBSD-SA-07:04.file
Main Index
Thread Index

CSIM home pageWMailAccount managementCSIM LibraryNetwork test toolsSearch CSIM directories
Contact us: Olivier Nicole CSIM    SET    AIT Last update: May 2007