From owner-freebsd-announce Wed Jun 26 12:10:50 2002 Delivered-To: freebsd-announce@freebsd.org Received: from freefall.freebsd.org (freefall.FreeBSD.org [216.136.204.21]) by hub.freebsd.org (Postfix) with ESMTP id F231C37BE47; Wed, 26 Jun 2002 12:08:22 -0700 (PDT) Received: from freefall.freebsd.org (nectar@localhost [127.0.0.1]) by freefall.freebsd.org (8.12.4/8.12.4) with ESMTP id g5QJ8MJU035396; Wed, 26 Jun 2002 12:08:22 -0700 (PDT) (envelope-from security-advisories@freebsd.org) Received: (from nectar@localhost) by freefall.freebsd.org (8.12.4/8.12.4/Submit) id g5QJ8MOE035394; Wed, 26 Jun 2002 12:08:22 -0700 (PDT) Date: Wed, 26 Jun 2002 12:08:22 -0700 (PDT) Message-Id: <200206261908.g5QJ8MOE035394@freefall.freebsd.org> X-Authentication-Warning: freefall.freebsd.org: nectar set sender to security-advisories@freebsd.org using -f From: FreeBSD Security Advisories To: FreeBSD Security Advisories Subject: FreeBSD Security Advisory FreeBSD-SA-02:28.resolv Reply-To: security-advisories@freebsd.org Sender: owner-freebsd-announce@FreeBSD.ORG Precedence: bulk List-ID: List-Archive: (Web Archive) List-Help: (List Instructions) List-Subscribe: List-Unsubscribe: X-Loop: FreeBSD.org -----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 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 . 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 -----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