-----BEGIN PGP SIGNED MESSAGE----- Hash: SHA1 ============================================================================= FreeBSD-SA-10:05.opie Security Advisory The FreeBSD Project Topic: OPIE off-by-one stack overflow Category: contrib Module: contrib_opie Announced: 2010-05-27 Credits: Maksymilian Arciemowicz and Adam Zabrocki Affects: All supported versions of FreeBSD Corrected: 2010-05-27 03:15:04 UTC (RELENG_8, 8.1-PRERELEASE) 2010-05-27 03:15:04 UTC (RELENG_8_0, 8.0-RELEASE-p3) 2010-05-27 03:15:04 UTC (RELENG_7, 7.3-STABLE) 2010-05-27 03:15:04 UTC (RELENG_7_3, 7.3-RELEASE-p1) 2010-05-27 03:15:04 UTC (RELENG_7_2, 7.2-RELEASE-p8) 2010-05-27 03:15:04 UTC (RELENG_7_1, 7.1-RELEASE-p12) 2010-05-27 03:15:04 UTC (RELENG_6, 6.4-STABLE) 2010-05-27 03:15:04 UTC (RELENG_6_4, 6.4-RELEASE-p10) CVE Name: CVE-2010-1938 For general information regarding FreeBSD Security Advisories, including descriptions of the fields above, security branches, and the following sections, please visit . I. Background OPIE is a one-time password system designed to help to secure a system against replay attacks. It does so using a secure hash function and a challenge/response system. OPIE is enabled by default on FreeBSD. II. Problem Description A programming error in the OPIE library could allow an off-by-one buffer overflow to write a single zero byte beyond the end of an on-stack buffer. III. Impact An attacker can remotely crash a service process which uses OPIE when stack protector is enabled. Note that this can happen even if OPIE is not enabled on the system, for instance the base system ftpd(8) is affected by this. Depending on the design and usage of OPIE, this may either affect only the process that handles the user authentication, or cause a Denial of Service condition. It is possible but very unlikely that an attacker could exploit this to gain access to a system. IV. Workaround No workaround is available, but systems without OPIE capable services running are not vulnerable. V. Solution Perform one of the following: 1) Upgrade your vulnerable system to 6-STABLE, 7-STABLE or 8-STABLE, or to the RELENG_8_0, RELENG_7_3, RELENG_7_2, RELENG_7_1, RELENG_6_4 security branch dated after the correction date. 2) To update your vulnerable system via a source code patch: The following patches have been verified to apply to FreeBSD 6.4, 7.1, 7.2, 7.3, and 8.0 systems. a) Download the relevant patch from the location below, and verify the detached PGP signature using your PGP utility. # fetch http://security.FreeBSD.org/patches/SA-10:05/opie.patch # fetch http://security.FreeBSD.org/patches/SA-10:05/opie.patch.asc b) Execute the following commands as root: # cd /usr/src # patch < /path/to/patch # cd /usr/src/lib/libopie # make obj && make depend && make && make install NOTE: On the amd64 platform, the above procedure will not update the lib32 (i386 compatibility) libraries. On amd64 systems where the i386 compatibility libraries are used, the operating system should instead be recompiled as described in 3) To update your vulnerable system via a binary patch: Systems running 6.4-RELEASE, 7.1-RELEASE, 7.2-RELEASE, 7.3-RELEASE or 8.0-RELEASE on the i386 or amd64 platforms can be updated via the freebsd-update(8) utility: # freebsd-update fetch # freebsd-update install VI. Correction details The following list contains the revision numbers of each file that was corrected in FreeBSD. CVS: Branch Revision Path - ------------------------------------------------------------------------- RELENG_6 src/contrib/opie/libopie/readrec.c 1.1.1.4.14.1 RELENG_6_4 src/UPDATING 1.416.2.40.2.14 src/sys/conf/newvers.sh 1.69.2.18.2.16 src/contrib/opie/libopie/readrec.c 1.1.1.4.26.1 RELENG_7 src/contrib/opie/libopie/readrec.c 1.2.2.1 RELENG_7_3 src/UPDATING 1.507.2.34.2.3 src/sys/conf/newvers.sh 1.72.2.16.2.5 src/contrib/opie/libopie/readrec.c 1.2.12.2 RELENG_7_2 src/UPDATING 1.507.2.23.2.11 src/sys/conf/newvers.sh 1.72.2.11.2.12 src/contrib/opie/libopie/readrec.c 1.2.8.2 RELENG_7_1 src/UPDATING 1.507.2.13.2.15 src/sys/conf/newvers.sh 1.72.2.9.2.16 src/contrib/opie/libopie/readrec.c 1.2.6.2 RELENG_8 src/contrib/opie/libopie/readrec.c 1.2.10.2 RELENG_8_0 src/UPDATING 1.632.2.7.2.6 src/sys/conf/newvers.sh 1.83.2.6.2.6 src/contrib/opie/libopie/readrec.c 1.2.10.1.2.2 - ------------------------------------------------------------------------- Subversion: Branch/path Revision - ------------------------------------------------------------------------- stable/6/ r208586 releng/6.4/ r208586 stable/7/ r208586 releng/7.3/ r208586 releng/7.2/ r208586 releng/7.1/ r208586 stable/8/ r208586 releng/8.0/ r208586 - ------------------------------------------------------------------------- VII. References http://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2010-1938 The latest revision of this advisory is available at http://security.FreeBSD.org/advisories/FreeBSD-SA-10:05.opie.asc -----BEGIN PGP SIGNATURE----- Version: GnuPG v1.4.10 (FreeBSD) iEYEARECAAYFAkv+sTQACgkQFdaIBMps37IDOACfReDDYdDp06vHNNxoovTPeVv2 ZBwAniPhGUNiWSa1hYFcW8RTIkJZNVcE =UFal -----END PGP SIGNATURE-----