FreeBSD Security Advisories
2015-Sep-02 21:07 UTC
[FreeBSD-Announce] FreeBSD Security Advisory FreeBSD-SA-15:23.bind
-----BEGIN PGP SIGNED MESSAGE----- Hash: SHA512 ============================================================================FreeBSD-SA-15:23.bind Security Advisory The FreeBSD Project Topic: BIND remote denial of service vulnerability Category: contrib Module: bind Announced: 2015-09-02 Credits: ISC Affects: FreeBSD 9.x Corrected: 2015-09-02 20:06:46 UTC (stable/9, 9.3-STABLE) 2015-09-02 20:07:03 UTC (releng/9.3, 9.3-RELEASE-p25) CVE Name: CVE-2015-5722 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) protocols. The named(8) daemon is an Internet Domain Name Server. The libdns library is a library of DNS protocol support functions. II. Problem Description Parsing a malformed DNSSEC key can cause a validating resolver to exit due to a failed assertion in buffer.c. III. Impact A remote attacker can deliberately trigger the failed assertion which will cause an affected server to terminate, by using a query that requires a response from a zone containing a malformed key, resulting in a denial of service condition. Recursive servers are at greatest risk, however, an authoritative server could also be affected, if an attacker controls a zone that the server must query against to perform its zone 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. The named 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 named 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. [FreeBSD 9.3] # fetch https://security.FreeBSD.org/patches/SA-15:23/bind.patch # fetch https://security.FreeBSD.org/patches/SA-15:23/bind.patch.asc # gpg --verify bind.patch.asc Please note that FreeBSD 9.3-STABLE is also affected by another issue (CVE-2015-5986), and a different patch should be used. 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 named(8) daemon, or reboot the system. VI. Correction details The following list contains the correction revision numbers for each affected branch. Branch/path Revision - ------------------------------------------------------------------------- stable/9/ r287409 releng/9.3/ r287410 - ------------------------------------------------------------------------- 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-01287> <URL:https://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2015-5722> CVE-2015-5986 is listed here for completeness and affects FreeBSD 9.3-STABLE but not FreeBSD 9.3-RELEASE: <URL:https://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2015-5986> The latest revision of this advisory is available at <URL:https://security.FreeBSD.org/advisories/FreeBSD-SA-15:23.bind.asc> -----BEGIN PGP SIGNATURE----- Version: GnuPG v2.1.7 (FreeBSD) iQIcBAEBCgAGBQJV52K9AAoJEO1n7NZdz2rnYQEP/1MY+pxPVMWT86qNKZ8upUpH LadLmtYAERrT9SMBrEFNCgylRdwNabTPKU0ZtxW8I57rks+j4bci053qo9Z7Hyo0 tbK3hTtxJZHNBO1G+NFfQxx9U+R+86Korx3NvDiB78XkJaab5On3dSgIMJYPEIL+ h0NEfYqe+X+LYg3W46faPdIuOsgxWSYN1T6mcZ5B5lucbT+LXjA5sRj+rUcE+a4O 2lIdM1oesWOZrEZo9FjK3UPvBbiEZkspr5IBd0zA825+BZNOpk06SOS/f3N0Pz8u S2vGlxcT37CzC9fPgjQpcNBmB+76xLgz74Inj4uPDSvCz+wmmcr95YOgheZb2N6K Bqakzy9TyRNk1aa8VXb8XpfyfMzroWG/vNjV6trI5wry7U0zRSl4dz+XAoz0A/eO 9ue88iWsVh97HBWKH94K8ZCA49G3NLgkbDkJ3awS4TfIKwwh9bGDiDepu1KMqnC1 EzyRk2fnr9JIreLj5zR1ctL1xGUvBIzWvHeT72PjgdZ/hqDoXTHKSVnDoR0c6T+U bJBJSLi3KUqaMkKRJez84r7G8RKtudLT292l4UQ3qgbiuaXagY6m1W0WBpLvw/zv RQOsG3HPpDrrV/LiSWKybEX2hIqIHd3tssfjQqvMa4WLO3h8wVONjw74YgRzZaYb t/1F4r4UYtfIJ7omydxx =B0u1 -----END PGP SIGNATURE-----