Date: Wed, 26 Jun 2002 13:33:34 -0600 From: Brett Glass <brett@lariat.org> To: security@FreeBSD.ORG Subject: Re: FreeBSD Security Advisory FreeBSD-SA-02:28.resolv Message-ID: <4.3.2.7.2.20020626133115.022a0d30@localhost> In-Reply-To: <200206261908.g5QJ8MOE035394@freefall.freebsd.org>
next in thread | previous in thread | raw e-mail | index | archive | help
Aaargh. This will affect not only more recent systems but the older 3.x and embedded systems I maintain for people. There's no patch for these, and in the case of the embedded systems that use BSD I can't upgrade. Any word on whether one can detect and block such attacks upstream via an IDS or a proxy at the firewall? --Brett Glass At 01:08 PM 6/26/2002, FreeBSD Security Advisories wrote: >-----BEGIN PGP SIGNED MESSAGE----- > >============================================================================= >FreeBSD-SA-02:28.resolv Security Advisory > The FreeBSD Project > >Topic: buffer overflow in resolver > >Category: core >Module: libc >Announced: 2002-06-26 >Credits: Joost Pol <joost@pine.nl> >Affects: All releases prior to and including 4.6-RELEASE >Corrected: 2002-06-26 06:34:18 UTC (RELENG_4) > 2002-06-26 08:44:24 UTC (RELENG_4_6) > 2002-06-26 18:53:20 UTC (RELENG_4_5) >FreeBSD only: NO > >I. Background > >The resolver implements functions for making, sending and interpreting >query and reply messages with Internet domain name servers. >Hostnames, IP addresses, and other information are queried using the >resolver. > >II. Problem Description > >DNS messages have specific byte alignment requirements, resulting in >padding in messages. In a few instances in the resolver code, this >padding is not taken into account when computing available buffer >space. As a result, the parsing of a DNS message may result in a >buffer overrun of up to a few bytes for each record included in the >message. > >III. Impact > >An attacker (either a malicious domain name server or an agent that >can spoof DNS messages) may produce a specially crafted DNS message >that will exploit this bug when parsed by an application using the >resolver. It may be possible for such an exploit to result in the >execution of arbitrary code with the privileges of the resolver-using >application. Though no exploits are known to exist today, since >practically all Internet applications utilize the resolver, the >severity of this issue is high. > >IV. Workaround > >There is currently no workaround. > >V. Solution > >Do one of the following: > >1) Upgrade your vulnerable system to 4.6-STABLE; or to the RELENG_4_6 >or RELENG_4_5 security branch dated after the correction date >(4.6-RELEASE-p1 or 4.5-RELEASE-p7). > >2) To patch your present system: > >The following patch has been verified to apply to FreeBSD 4.5 and >FreeBSD 4.6 systems. > >a) Download the relevant patch from the location below, and verify the >detached PGP signature using your PGP utility. > ># fetch ftp://ftp.FreeBSD.org/pub/FreeBSD/CERT/patches/SA-02:28/resolv.patch ># fetch ftp://ftp.FreeBSD.org/pub/FreeBSD/CERT/patches/SA-02:28/resolv.patch.asc > >b) Execute the following commands as root: > ># cd /usr/src ># patch < /path/to/patch > >c) Recompile the operating systems as described in ><URL:http://www.freebsd.org/doc/handbook/makeworld.html>. > >Note that any statically linked applications that are not part of >the base system (i.e. from the Ports Collection or other 3rd-party >sources) must be recompiled. > >VI. Correction details > >The following list contains the revision numbers of each file that was >corrected in FreeBSD. > >Path Revision > Branch >- ------------------------------------------------------------------------- >src/lib/libc/net/gethostbydns.c > RELENG_4 1.27.2.2 > RELENG_4_6 1.27.10.1 > RELENG_4_5 1.27.8.1 >src/lib/libc/net/getnetbydns.c > RELENG_4 1.13.2.2 > RELENG_4_6 1.13.2.1.8.1 > RELENG_4_5 1.13.2.1.6.1 >src/lib/libc/net/name6.c > RELENG_4 1.6.2.6 > RELENG_4_6 1.6.2.5.8.1 > RELENG_4_5 1.6.2.5.6.1 >src/sys/conf/newvers.sh > RELENG_4_6 1.44.2.23.2.2 > RELENG_4_5 1.44.2.20.2.8 >- ------------------------------------------------------------------------- > >VII. References > ><URL:http://www.pine.nl/advisories/pine-cert-20020601.html>; >-----BEGIN PGP SIGNATURE----- >Version: GnuPG v1.0.7 (FreeBSD) > >iQCVAwUBPRoQOVUuHi5z0oilAQG3cAP/d7Gb2rdkSjZKCR0NI+QzMibgySVTXOtF >sdoJrYka/XnIpFMVAyXl36bibtRKbwfCyv/rEX39YSas7tqReizwAABoaRF956Qb >qlek1ONvvd+Tj6+WpEEueX/VdPqGQuqMk0BoguIbOgwAya6ZFYJ9ZKAHHSN9YqO8 >ZGTC8pmqfGI= >=s76v >-----END PGP SIGNATURE----- > >This is the moderated mailing list freebsd-announce. >The list contains announcements of new FreeBSD capabilities, >important events and project milestones. >See also the FreeBSD Web pages at http://www.freebsd.org > > >To Unsubscribe: send mail to majordomo@FreeBSD.org >with "unsubscribe freebsd-announce" in the body of the message To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-security" in the body of the message
Want to link to this message? Use this URL: <https://mail-archive.FreeBSD.org/cgi/mid.cgi?4.3.2.7.2.20020626133115.022a0d30>