-----BEGIN PGP SIGNED MESSAGE----- Hash: SHA1 ============================================================================= FreeBSD-SA-09:15.ssl Security Advisory The FreeBSD Project Topic: SSL protocol flaw Category: contrib Module: openssl Announced: 2009-12-03 Credits: Marsh Ray, Steve Dispensa Affects: All supported versions of FreeBSD. Corrected: 2009-12-03 09:18:40 UTC (RELENG_8, 8.0-STABLE) 2009-12-03 09:18:40 UTC (RELENG_8_0, 8.0-RELEASE-p1) 2009-12-03 09:18:40 UTC (RELENG_7, 7.2-STABLE) 2009-12-03 09:18:40 UTC (RELENG_7_2, 7.2-RELEASE-p5) 2009-12-03 09:18:40 UTC (RELENG_7_1, 7.1-RELEASE-p9) 2009-12-03 09:18:40 UTC (RELENG_6, 6.4-STABLE) 2009-12-03 09:18:40 UTC (RELENG_6_4, 6.4-RELEASE-p8) 2009-12-03 09:18:40 UTC (RELENG_6_3, 6.3-RELEASE-p14) CVE Name: CVE-2009-3555 For general information regarding FreeBSD Security Advisories, including descriptions of the fields above, security branches, and the following sections, please visit . 0. Revision History v1.0 2009-12-03 Initial release. v1.1 2009-12-03 Corrected instructions in section V.2)b). I. Background The SSL (Secure Sockets Layer) and TLS (Transport Layer Security) protocols provide a secure communications layer over which other protocols can be utilized. The most widespread use of SSL/TLS is to add security to the HTTP protocol, thus producing HTTPS. FreeBSD includes software from the OpenSSL Project which implements SSL and TLS. II. Problem Description The SSL version 3 and TLS protocols support session renegotiation without cryptographically tying the new session parameters to the old parameters. III. Impact An attacker who can intercept a TCP connection being used for SSL or TLS can cause the initial session negotiation to take the place of a session renegotiation. This can be exploited in several ways, including: * Causing a server to interpret incoming messages as having been sent under the auspices of a client SSL key when in fact they were not; * Causing a client request to be appended to an attacker-supplied request, potentially revealing to the attacker the contents of the client request (including any authentication parameters); and * Causing a client to receive a response to an attacker-supplied request instead of a response to the request sent by the client. IV. Workaround No workaround is available. V. Solution NOTE WELL: This update causes OpenSSL to reject any attempt to renegotiate SSL / TLS session parameters. As a result, connections in which the other party attempts to renegotiate session parameters will break. In practice, however, session renegotiation is a rarely-used feature, so disabling this functionality is unlikely to cause problems for most systems. 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_2, RELENG_7_1, RELENG_6_4, or RELENG_6_3 security branch dated after the correction date. 2) To patch your present system: The following patches have been verified to apply to FreeBSD 6.3, 6.4, 7.1, 7.2, 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-09:15/ssl.patch # fetch http://security.FreeBSD.org/patches/SA-09:15/ssl.patch.asc b) Execute the following commands as root: # cd /usr/src # patch < /path/to/patch # cd /usr/src/secure/lib/libssl # make obj && make depend && make includes && 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 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/crypto/openssl/ssl/s3_pkt.c 1.1.1.10.2.1 src/crypto/openssl/ssl/s3_srvr.c 1.1.1.14.2.3 src/crypto/openssl/ssl/s3_lib.c 1.1.1.10.2.1 RELENG_6_4 src/UPDATING 1.416.2.40.2.12 src/sys/conf/newvers.sh 1.69.2.18.2.14 src/crypto/openssl/ssl/s3_pkt.c 1.1.1.10.12.1 src/crypto/openssl/ssl/s3_srvr.c 1.1.1.14.2.1.6.2 src/crypto/openssl/ssl/s3_lib.c 1.1.1.10.12.1 RELENG_6_3 src/UPDATING 1.416.2.37.2.19 src/sys/conf/newvers.sh 1.69.2.15.2.18 src/crypto/openssl/ssl/s3_pkt.c 1.1.1.10.10.1 src/crypto/openssl/ssl/s3_srvr.c 1.1.1.14.2.1.4.2 src/crypto/openssl/ssl/s3_lib.c 1.1.1.10.10.1 RELENG_7 src/crypto/openssl/ssl/s3_pkt.c 1.1.1.12.2.1 src/crypto/openssl/ssl/s3_srvr.c 1.1.1.17.2.2 src/crypto/openssl/ssl/s3_lib.c 1.1.1.13.2.1 RELENG_7_2 src/UPDATING 1.507.2.23.2.8 src/sys/conf/newvers.sh 1.72.2.11.2.9 src/crypto/openssl/ssl/s3_pkt.c 1.1.1.12.8.1 src/crypto/openssl/ssl/s3_srvr.c 1.1.1.17.2.1.2.1 src/crypto/openssl/ssl/s3_lib.c 1.1.1.13.8.1 RELENG_7_1 src/UPDATING 1.507.2.13.2.12 src/sys/conf/newvers.sh 1.72.2.9.2.13 src/crypto/openssl/ssl/s3_pkt.c 1.1.1.12.6.1 src/crypto/openssl/ssl/s3_srvr.c 1.1.1.17.6.2 src/crypto/openssl/ssl/s3_lib.c 1.1.1.13.6.1 RELENG_8 src/crypto/openssl/ssl/s3_pkt.c 1.2.2.1 src/crypto/openssl/ssl/s3_srvr.c 1.3.2.1 src/crypto/openssl/ssl/s3_lib.c 1.2.2.1 RELENG_8_0 src/UPDATING 1.632.2.7.2.4 src/sys/conf/newvers.sh 1.83.2.6.2.4 src/crypto/openssl/ssl/s3_pkt.c 1.2.4.1 src/crypto/openssl/ssl/s3_srvr.c 1.3.4.1 src/crypto/openssl/ssl/s3_lib.c 1.2.4.1 - ------------------------------------------------------------------------- Subversion: Branch/path Revision - ------------------------------------------------------------------------- stable/6/ r200054 releng/6.4/ r200054 releng/6.3/ r200054 stable/7/ r200054 releng/7.2/ r200054 releng/7.1/ r200054 - ------------------------------------------------------------------------- VII. References http://extendedsubset.com/Renegotiating_TLS.pdf http://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2009-3555 The latest revision of this advisory is available at http://security.FreeBSD.org/advisories/FreeBSD-SA-09:15.ssl.asc -----BEGIN PGP SIGNATURE----- Version: GnuPG v1.4.10 (FreeBSD) iEYEARECAAYFAksYIm4ACgkQFdaIBMps37J5jwCZAQurPSu2CyGz2thi8ljb+MlF LcwAnjSLYWT1nV5G9a46n9zcrpEqydJ3 =XuZD -----END PGP SIGNATURE-----