3571e53040
patches for easier mirroring, to eliminate a special copy, to make www.freebsd.org/security a full copy of security.freebsd.org and be eventually be the same. For now files are just sitting there. The symlinks are missing. Discussed on: www (repository location) Discussed with: simon (so)
156 lines
6.2 KiB
Text
156 lines
6.2 KiB
Text
-----BEGIN PGP SIGNED MESSAGE-----
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Hash: SHA1
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=============================================================================
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FreeBSD-SA-06:20.bind Security Advisory
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The FreeBSD Project
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Topic: Denial of Service in named(8)
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Category: contrib
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Module: bind
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Announced: 2006-09-06
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Credits: The Measurement Factory
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Affects: FreeBSD 5.3 and later.
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Corrected: 2006-09-06 21:18:26 UTC (RELENG_6, 6.1-STABLE)
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2006-09-06 21:19:21 UTC (RELENG_6_1, 6.1-RELEASE-p6)
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2006-09-06 21:20:08 UTC (RELENG_6_0, 6.0-RELEASE-p11)
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2006-09-06 21:20:54 UTC (RELENG_5, 5.5-STABLE)
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2006-09-06 21:21:50 UTC (RELENG_5_5, 5.5-RELEASE-p4)
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2006-09-06 21:22:39 UTC (RELENG_5_4, 5.4-RELEASE-p18)
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2006-09-06 21:23:16 UTC (RELENG_5_3, 5.3-RELEASE-p33)
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CVE Name: CVE-2006-4095, CVE-2006-4096
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For general information regarding FreeBSD Security Advisories,
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including descriptions of the fields above, security branches, and the
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following sections, please visit
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<URL:http://security.freebsd.org/>.
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I. Background
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BIND 9 is an implementation of the Domain Name System (DNS) protocols.
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The named(8) daemon is an Internet domain name server. DNS Security
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Extensions (DNSSEC) are additional protocol options that add
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authentication and integrity to the DNS protocols.
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II. Problem Description
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For a recursive DNS server, a remote attacker sending enough recursive
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queries for the replies to arrive after all the interested clients
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have left the recursion queue will trigger an INSIST failure in the
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named(8) daemon. Also for a recursive DNS server, an assertion
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failure can occur when processing a query whose reply will contain
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more than one SIG(covered) RRset.
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For an authoritative DNS server serving a RFC 2535 DNSSEC zone which
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is queried for the SIG records where there are multiple SIG(covered)
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RRsets (e.g. a zone apex), named(8) will trigger an assertion failure
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when it tries to construct the response.
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III. Impact
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An attacker who can perform recursive lookups on a DNS server and is able
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to send a sufficiently large number of recursive queries, or is able to
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get the DNS server to return more than one SIG(covered) RRsets can stop
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the functionality of the DNS service.
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An attacker querying an authoritative DNS server serving a RFC 2535
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DNSSEC zone may be able to crash the DNS server.
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All of the above issues will result in a Denial of Service situation.
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IV. Workaround
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A possible workaround is to only allow trusted clients to perform recursive
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queries.
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V. Solution
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Perform one of the following:
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1) Upgrade your vulnerable system to 5-STABLE, or 6-STABLE, or to the
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RELENG_6_1, RELENG_6_0, RELENG_5_5, RELENG_5_4, or RELENG_5_3 security
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branch dated after the correction date.
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2) To patch your present system:
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The following patches have been verified to apply to FreeBSD 5.3, 5.4,
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5.5, 6.0, and 6.1 systems.
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a) Download the relevant patch from the location below, and verify the
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detached PGP signature using your PGP utility.
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# fetch http://security.FreeBSD.org/patches/SA-06:20/bind.patch
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# fetch http://security.FreeBSD.org/patches/SA-06:20/bind.patch.asc
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b) Execute the following commands as root:
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# cd /usr/src
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# patch < /path/to/patch
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# cd /usr/src/lib/bind
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# make obj && make depend && make && make install
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# cd /usr/src/usr.sbin/named
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# make obj && make depend && make && make install
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c) Restart the named application:
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# /etc/rc.d/named restart
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VI. Correction details
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The following list contains the revision numbers of each file that was
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corrected in FreeBSD.
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Branch Revision
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Path
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- -------------------------------------------------------------------------
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RELENG_5
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src/contrib/bind9/bin/named/query.c 1.1.1.1.2.3
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src/contrib/bind9/lib/dns/resolver.c 1.1.1.1.2.5
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RELENG_5_5
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src/UPDATING 1.342.2.35.2.4
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src/sys/conf/newvers.sh 1.62.2.21.2.6
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src/contrib/bind9/bin/named/query.c 1.1.1.1.2.2.2.1
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src/contrib/bind9/lib/dns/resolver.c 1.1.1.1.2.4.2.1
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RELENG_5_4
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src/UPDATING 1.342.2.24.2.27
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src/sys/conf/newvers.sh 1.62.2.18.2.23
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src/contrib/bind9/bin/named/query.c 1.1.1.1.2.1.4.1
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src/contrib/bind9/lib/dns/resolver.c 1.1.1.1.2.2.2.1
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RELENG_5_3
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src/UPDATING 1.342.2.13.2.36
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src/sys/conf/newvers.sh 1.62.2.15.2.38
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src/contrib/bind9/bin/named/query.c 1.1.1.1.2.1.2.1
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src/contrib/bind9/lib/dns/resolver.c 1.1.1.1.2.1.2.1
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RELENG_6
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src/contrib/bind9/bin/named/query.c 1.1.1.1.4.2
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src/contrib/bind9/lib/dns/resolver.c 1.1.1.2.2.3
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RELENG_6_1
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src/UPDATING 1.416.2.22.2.8
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src/sys/conf/newvers.sh 1.69.2.11.2.8
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src/contrib/bind9/bin/named/query.c 1.1.1.1.4.1.2.1
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src/contrib/bind9/lib/dns/resolver.c 1.1.1.2.2.2.2.1
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RELENG_6_0
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src/UPDATING 1.416.2.3.2.16
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src/sys/conf/newvers.sh 1.69.2.8.2.12
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src/contrib/bind9/bin/named/query.c 1.1.1.1.6.1
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src/contrib/bind9/lib/dns/resolver.c 1.1.1.2.2.1.2.1
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- -------------------------------------------------------------------------
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VII. References
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http://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2006-4095
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http://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2006-4096
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http://www.kb.cert.org/vuls/id/697164
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http://www.kb.cert.org/vuls/id/915404
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http://www.niscc.gov.uk/niscc/docs/re-20060905-00590.pdf?lang=en
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The latest revision of this advisory is available at
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http://security.FreeBSD.org/advisories/FreeBSD-SA-06:20.bind.asc
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