-----BEGIN PGP SIGNED MESSAGE----- Hash: SHA512 ============================================================================= FreeBSD-SA-15:11.bind Security Advisory The FreeBSD Project Topic: BIND resolver remote denial of service when validating Category: contrib Module: bind Announced: 2015-07-07 Credits: ISC Affects: FreeBSD 8.4 and FreeBSD 9.3. Corrected: 2015-07-07 21:43:23 UTC (stable/9, 9.3-STABLE) 2015-07-07 21:44:01 UTC (releng/9.3, 9.3-RELEASE-p19) 2015-07-07 21:43:23 UTC (stable/8, 8.4-STABLE) 2015-07-07 21:44:01 UTC (releng/8.4, 8.4-RELEASE-p33) CVE Name: CVE-2015-4620 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 BIND 9 is an implementation of the Domain Name System (DNS) protocol. The named(8) daemon is an Internet Domain Name Server. The libdns library is a library of DNS protocol support functions. II. Problem Description Due to a software defect, specially constructed zone data could cause named(8) to crash with an assertion failure and rejecting the malformed query when DNSSEC validation is enabled. III. Impact An attacker who can cause specific queries to be sent to a nameserver could cause named(8) to crash, resulting in a denial of service. IV. Workaround No workaround is available, but hosts not running named(8) are not vulnerable. 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. 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 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. [FreeBSD 9.3] # fetch https://security.FreeBSD.org/patches/SA-15:11/bind-9.patch # fetch https://security.FreeBSD.org/patches/SA-15:11/bind-9.patch.asc # gpg --verify bind-9.patch.asc [FreeBSD 8.4] # fetch https://security.FreeBSD.org/patches/SA-15:11/bind-8.patch # fetch https://security.FreeBSD.org/patches/SA-15:11/bind-8.patch.asc # gpg --verify bind-8.patch.asc b) Apply the patch. Execute the following commands as root: # cd /usr/src # patch < /path/to/patch c) Recompile the operating system using buildworld and installworld as described in <URL:https://www.FreeBSD.org/handbook/makeworld.html>. Restart the applicable daemons, or reboot the system. VI. Correction details The following list contains the correction revision numbers for each affected branch. Branch/path Revision - ------------------------------------------------------------------------- stable/8/ r285257 releng/8.4/ r285258 stable/9/ r285257 releng/9.3/ r285258 - ------------------------------------------------------------------------- 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://kb.isc.org/article/AA-01267/> <URL:https://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2015-4620> The latest revision of this advisory is available at <URL:https://security.FreeBSD.org/advisories/FreeBSD-SA-15:11.bind.asc> -----BEGIN PGP SIGNATURE----- Version: GnuPG v2.1.5 (FreeBSD) iQIcBAEBCgAGBQJVnEi/AAoJEO1n7NZdz2rnw4cP/jg5odJDqjzynxVweq+rCo7q 10Wwa5Is3BOFAMxE+qVvIyjPKwBTlYOud4Lwp9+6GXpEa6DQDTrqwGsgsEKsqrNN WF8mfOhsSSHuhKNdcCT3+9/ERhdS6JwmvIgMhmEvBAWhf2HA6FRPQ1J6TP0ZoGKm 0x745/cqiYM4eCwH8kbC1tmMYBHqYapuI9aTZ8iuiddBR1lunE03GVlNn1A6e2U6 CUt6rHNslup4C7sGq6fBt/5qlJZ4yOGCXHDys9l0OSeYUfKohbDi2TILhoMhio2x 8OdFIdr5U7sOtLPirbfLAUTb1C/H/BsKZfIX3Ff7iZQruVQrU4hKR1hd+GjZQb2G 5foI9jP3AIRZ3xaHjH0Y95/4diJz+nauH5BTeD9OLGJC3Mg/NsVVtoflg3o+AWKn 692ovG1csdkT598K0VV7Kp36n4tR43SPFZ8bqo8TMdt40H9imaN7ghXOFhpG1Yw8 A6EU/yHJ5Jn9XyGM0E803pFodZEQk8wM8/LllA1txz85eDy+6HOQsxJeROcwJFeH rtzJ6bweqV3keJPkP/AR+QLqFMEbySHp2al7uGAIHyd/3fGlvWhP10CTyxvG7ucY Ak9PwH11UTw+RexOhOTWF+Bz9A5vVWG/wDPfGFLbhdmK00gX4y9xNOk2/QP6fTL3 8Sz9sMkdOx3Vrbq+PPmu =SVcF -----END PGP SIGNATURE-----