FreeBSD Security Advisory FreeBSD-SA-12:05.bind

-----BEGIN PGP SIGNED MESSAGE----- Hash: SHA1 ============================================================================= FreeBSD-SA-12:05.bind Security Advisory The FreeBSD Project Topic: named(8) DNSSEC validation Denial of Service Category: contrib Module: bind Announced: 2012-08-06 Credits: Einar Lonn of IIS.se Affects: All supported versions of FreeBSD Corrected: 2012-08-06 21:33:11 UTC (RELENG_7, 7.4-STABLE) 2012-08-06 21:33:11 UTC (RELENG_7_4, 7.4-RELEASE-p10) 2012-07-24 19:04:35 UTC (RELENG_8, 8.3-STABLE) 2012-08-06 21:33:11 UTC (RELENG_8_3, 8.3-RELEASE-p4) 2012-08-06 21:33:11 UTC (RELENG_8_2, 8.2-RELEASE-p10) 2012-08-06 21:33:11 UTC (RELENG_8_1, 8.1-RELEASE-p13) 2012-07-24 22:32:03 UTC (RELENG_9, 9.1-PRERELEASE) 2012-08-06 21:33:11 UTC (RELENG_9_0, 9.0-RELEASE-p4) CVE Name: CVE-2012-3817 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 BIND 9 is an implementation of the Domain Name System (DNS) protocols. The named(8) daemon is an Internet Domain Name Server. DNS Security Extensions (DNSSEC) provides data integrity, origin authentication and authenticated denial of existence to resolvers. II. Problem Description BIND 9 stores a cache of query names that are known to be failing due to misconfigured name servers or a broken chain of trust. Under high query loads, when DNSSEC validation is active, it is possible for a condition to arise in which data from this cache of failing queries could be used before it was fully initialized, triggering an assertion failure. III. Impact A remote attacker that is able to generate high volume of DNSSEC validation enabled queries can trigger the assertion failure that causes it to crash, resulting in a denial of service. IV. Workaround No workaround is available, but systems not running the BIND resolving name server with dnssec-validation enabled are not affected. V. Solution Perform one of the following: 1) Upgrade your vulnerable system to 7-STABLE, 8-STABLE, or 9-STABLE, or to the RELENG_7_4, RELENG_8_3, RELENG_8_2, RELENG_8_1, or RELENG_9_0 security branch dated after the correction date. 2) To update your vulnerable system via a source code patch: The following patches have been verified to apply to FreeBSD 7.4, 8.3, 8.2, 8.1 and 9.0 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-12:05/bind.patch # fetch http://security.FreeBSD.org/patches/SA-12:05/bind.patch.asc b) Execute the following commands as root: # cd /usr/src # patch < /path/to/patch # cd /usr/src/lib/bind/dns # make obj && make depend && make && make install # cd /usr/src/usr.sbin/named # make obj && make depend && make && make install 3) To update your vulnerable system via a binary patch: Systems running 7.4-RELEASE, 8.3-RELEASE, 8.2-RELEASE, 8.1-RELEASE, or 9.0-RELEASE on the i386 or amd64 platforms can be updated via the freebsd-update(8) utility: # freebsd-update fetch # freebsd-update install 4) Install and run BIND from the Ports Collection after the correction date. The following versions and newer versions of BIND installed from the Ports Collection are not affected by this vulnerability: bind96-9.6.3.1.ESV.R7.2 bind97-9.7.6.2 bind98-9.8.3.2 bind99-9.9.1.2 VI. Correction details The following list contains the revision numbers of each file that was corrected in FreeBSD. CVS: Branch Revision Path - ------------------------------------------------------------------------- RELENG_7 src/contrib/bind9/lib/dns/resolver.c 1.1.1.9.2.11 RELENG_7_4 src/UPDATING 1.507.2.36.2.12 src/sys/conf/newvers.sh 1.72.2.18.2.15 src/contrib/bind9/lib/dns/resolver.c 1.1.1.9.2.8.2.1 RELENG_8 src/contrib/bind9/CHANGES 1.9.2.15 src/contrib/bind9/lib/dns/resolver.c 1.3.2.6 src/contrib/bind9/lib/dns/zone.c 1.6.2.10 src/contrib/bind9/lib/isc/random.c 1.2.2.4 src/contrib/bind9/version 1.9.2.15 RELENG_8_3 src/UPDATING 1.632.2.26.2.6 src/sys/conf/newvers.sh 1.83.2.15.2.8 src/contrib/bind9/lib/dns/resolver.c 1.6.2.7.2.1 RELENG_8_2 src/UPDATING 1.632.2.19.2.12 src/sys/conf/newvers.sh 1.83.2.12.2.15 src/contrib/bind9/lib/dns/resolver.c 1.6.2.4.2.1 RELENG_8_1 src/UPDATING 1.632.2.14.2.16 src/sys/conf/newvers.sh 1.83.2.10.2.17 src/contrib/bind9/lib/dns/resolver.c 1.6.2.3.2.1 RELENG_9 src/contrib/bind9/CHANGES 1.21.2.5 src/contrib/bind9/lib/dns/resolver.c 1.15.2.3 src/contrib/bind9/lib/dns/zone.c 1.7.2.3 src/contrib/bind9/version 1.21.2.5 RELENG_9_0 src/UPDATING 1.702.2.4.2.6 src/sys/conf/newvers.sh 1.95.2.4.2.8 src/contrib/bind9/lib/dns/resolver.c 1.15.4.1 - ------------------------------------------------------------------------- Subversion: Branch/path Revision - ------------------------------------------------------------------------- stable/7/ r239108 releng/7.4/ r239108 stable/8/ r238749 releng/8.3/ r239108 releng/8.2/ r239108 releng/8.1/ r239108 stable/9/ r238756 releng/9.0/ r239108 - ------------------------------------------------------------------------- VII. References https://kb.isc.org/article/AA-00729 http://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2012-3817 The latest revision of this advisory is available at http://security.FreeBSD.org/advisories/FreeBSD-SA-12:05.bind.asc -----BEGIN PGP SIGNATURE----- Version: GnuPG v1.4.9 iEYEARECAAYFAlAgP6kACgkQFdaIBMps37KLuQCfdF1xHFsD5vgeWKeTfPo1z0UG XN8AnRZQy5itaoFPFALXoDy3ZnZ5qA1t =hvTi -----END PGP SIGNATURE-----