|
FreeBSD-SA-08:10 - IPv6 Neighbor Discovery Protocol routing vulnerability |
|
|
|
|
Written by Astharot
|
|
Thursday, 02 October 2008 |
The
FreeBSD Project
Topic: IPv6 Neighbor Discovery Protocol routing
vulnerability
Category: core
Module: sys_netinet6
Announced: 2008-10-01
Credits: David
Miles
Affects: All supported versions of FreeBSD.
Corrected: 2008-10-01 00:32:59 UTC (RELENG_7, 7.1-PRERELEASE)
2008-10-01
00:32:59 UTC (RELENG_7_0, 7.0-RELEASE-p5)
2008-10-01 00:32:59
UTC (RELENG_6, 6.4-PRERELEASE)
2008-10-01 00:32:59 UTC
(RELENG_6_3, 6.3-RELEASE-p5)
CVE Name: CVE-2008-2476
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 the Neighbor Discovery protocol to determine
the link-layer address of other nodes, find routers, and maintain
reachability information.
The Neighbor Discovery protocol uses Neighbor
Solicitation (ICMPv6 type 135) to query target nodes for their link-layer
addresses...
II. Problem Description
IPv6 routers may allow
"on-link" IPv6 nodes to create and update the router's neighbor cache and
forwarding information. A malicious IPv6 node sharing a common router but on
a different physical segment from another node may be able to spoof Neighbor
Discovery messages, allowing it to update router information for the victim
node.
III. Impact
An attacker on a different physical network
connected to the same IPv6 router as another node could redirect IPv6 traffic
intended for that node. This could lead to denial of service or improper
access to private network
traffic.
IV. Workaround
Firewall
packet filters can be used to filter incoming Neighbor Solicitation messages
but may interfere with normal IPv6 operation if not configured
carefully.
Reverse path forwarding checks could be used to make gateways,
such as routers or firewalls, drop Neighbor Solicitation messages
from nodes with unexpected source addresses on a particular
interface.
IPv6 router administrators are encouraged to read RFC 3756 for
further discussion of Neighbor Discovery security implications.
V.
Solution
NOTE WELL: The solution described below causes IPv6 Neighbor
Discovery Neighbor Solicitation messages from non-neighbors to be
ignored.
This can be re-enabled if required by setting the newly
added net.inet6.icmp6.nd6_onlink_ns_rfc4861 sysctl to a non-zero
value.
Perform one of the following:
1) Upgrade your vulnerable
system to 6-STABLE, or 7-STABLE, or to the RELENG_7_0, or RELENG_6_3 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 7.0 systems.
a) Download the relevant patch from the location
below, and verify the detached PGP signature using your PGP
utility.
[FreeBSD 6.3]
# fetch http://security.FreeBSD.org/patches/SA-08:10/nd6-6.patch
#
fetch http://security.FreeBSD.org/patches/SA-08:10/nd6-6.patch.asc
[FreeBSD
7.0]
# fetch http://security.FreeBSD.org/patches/SA-08:10/nd6-7.patch
#
fetch http://security.FreeBSD.org/patches/SA-08:10/nd6-7.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/in6.h 1.36.2.10
src/sys/netinet6/in6_proto.c 1.32.2.10
src/sys/netinet6/nd6.h 1.19.2.4
src/sys/netinet6/nd6_nbr.c
1.29.2.11
RELENG_6_3
src/UPDATING 1.416.2.37.2.10
src/sys/conf/newvers.sh 1.69.2.15.2.9
src/sys/netinet6/in6.h 1.36.2.8.2.1
src/sys/netinet6/in6_proto.c 1.32.2.8.2.1
src/sys/netinet6/nd6.h 1.19.2.2.6.1
src/sys/netinet6/nd6_nbr.c
1.29.2.9.2.1
RELENG_7
src/sys/netinet6/in6.h 1.51.2.2
src/sys/netinet6/in6_proto.c 1.46.2.3
src/sys/netinet6/nd6.h 1.21.2.2
src/sys/netinet6/nd6_nbr.c
1.47.2.3
RELENG_7_0
src/UPDATING 1.507.2.3.2.9
src/sys/conf/newvers.sh 1.72.2.5.2.9
src/sys/netinet6/in6.h 1.51.4.1
src/sys/netinet6/in6_proto.c 1.46.4.1
src/sys/netinet6/nd6.h 1.21.4.1
src/sys/netinet6/nd6_nbr.c 1.47.4.1
-
-------------------------------------------------------------------------
VII.
References
http://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2008-2476
http://www.kb.cert.org/vuls/id/472363
The
latest revision of this advisory is available at
http://security.FreeBSD.org/advisories/FreeBSD-SA-08:10.nd6.asc
|
 |
Powered by a Zone-H(ified) version of AkoComment 3.0!
DISCLAIMER: Forum postings are the opinion of the posting author alone, and should not be taken as the opinion of Zone-h. The author is entirely and solely responsible for all content that he/she uploads, posts, or otherwise transmits via the website. Zone-h is not responsible for such content. However, Zone-h shall have the right, but not the obligation, to delete, move, or edit any content that violates this agreement or is otherwise objectionable as determined by Zone-h in its sole discretion and without notice. |
