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Posted on 06 August 2015
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FreeBSD-SA-15:19.routed Security Advisory
The FreeBSD Project
Topic: routed(8) remote denial of service vulnerability
Category: core
Module: routed
Announced: 2015-08-05
Credits: Hiroki Sato
Affects: All supported versions of FreeBSD.
Corrected: 2015-08-05 22:05:02 UTC (stable/10, 10.2-PRERELEASE)
2015-08-05 22:05:02 UTC (stable/10, 10.2-BETA2-p3)
2015-08-05 22:05:12 UTC (releng/10.2, 10.2-RC1-p2)
2015-08-05 22:05:12 UTC (releng/10.2, 10.2-RC2-p1)
2015-08-05 22:05:18 UTC (releng/10.1, 10.1-RELEASE-p17)
2015-08-05 22:05:07 UTC (stable/9, 9.3-STABLE)
2015-08-05 22:05:24 UTC (releng/9.3, 9.3-RELEASE-p22)
CVE Name: CVE-2015-5674
For general information regarding FreeBSD Security Advisories,
including descriptions of the fields above, security branches, and the
following sections, please visit <URL:https://security.FreeBSD.org/>.
I. Background
The routing information protocol (RIP) is an older routing protocol
which, while not as capable as more recent protocols such as OSPF and
BGP, is sometimes preferred for its simplicity and therefore still
used as an interior gateway protocol on smaller networks.
Routers in a RIP network periodically broadcast their routing table on
all enabled interfaces. Neighboring routers and hosts receive these
broadcasts and update their routing tables accordingly.
The routed(8) daemon is a RIP implementation for FreeBSD. The
rtquery(8) utility can be used to send a RIP query to a router and
display the result without updating the routing table.
II. Problem Description
The input path in routed(8) will accept queries from any source and
attempt to answer them. However, the output path assumes that the
destination address for the response is on a directly connected
network.
III. Impact
Upon receipt of a query from a source which is not on a directly
connected network, routed(8) will trigger an assertion and terminate.
The affected system's routing table will no longer be updated. If the
affected system is a router, its routes will eventually expire from
other routers' routing tables, and its networks will no longer be
reachable unless they are also connected to another router.
IV. Workaround
Note that this problem does not affect a system on which routed(8)
is not enabled. The routed(8) daemon is not enabled by default.
Use a packet filter such as pf(4) or ipfw(4) to block incoming UDP
packets with destination port 520 that did not originate on the same
subnet as the destination address.
V. Solution
Perform one of the following:
1) Upgrade your vulnerable system to a supported FreeBSD stable or
release / security branch (releng) dated after the correction date.
The routed service has to be restarted after the update. A reboot is
recommended but not required.
2) To update your vulnerable system via a binary patch:
Systems running a RELEASE version of FreeBSD on the i386 or amd64
platforms can be updated via the freebsd-update(8) utility:
# freebsd-update fetch
# freebsd-update install
The routed service has to be restarted after the update. A reboot is
recommended but not required.
3) To update your vulnerable system via a source code patch:
The following patches have been verified to apply to the applicable
FreeBSD release branches.
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-15:19/routed.patch
# fetch http://security.FreeBSD.org/patches/SA-15:19/routed.patch.asc
# gpg --verify routed.patch.asc
b) Apply the patch. Execute the following commands as root:
# cd /usr/src
# patch < /path/to/routed.patch
c) Recompile routed. Execute the following commands as root:
# cd /usr/src/sbin/routed
# make && make install
Restart the routed daemon, or reboot the system.
To restart the affected service after updating the system, either
reboot the system or execute the following command as root:
# service routed restart
VI. Correction details
The following list contains the correction revision numbers for each
affected branch.
Branch/path Revision
- -------------------------------------------------------------------------
stable/9/ r286349
releng/9.3/ r286352
stable/10/ r286348
releng/10.1/ r286351
releng/10.2/ r286350
- -------------------------------------------------------------------------
To see which files were modified by a particular revision, run the
following command, replacing NNNNNN with the revision number, on a
machine with Subversion installed:
# svn diff -cNNNNNN --summarize svn://svn.freebsd.org/base
Or visit the following URL, replacing NNNNNN with the revision number:
<URL:https://svnweb.freebsd.org/base?view=revision&revision=NNNNNN>
VII. References
<URL:https://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2015-5674>
The latest revision of this advisory is available at
<URL:http://security.FreeBSD.org/advisories/FreeBSD-SA-15:19.routed.asc>
