FreeBSD Security Advisory FreeBSD-SA-16:11.openssl

Fabricante: FreeBSD
Fecha: 30/01/2016
Identificador: FreeBSD-SA-16:11.openssl
FreeBSD Security Advisory FreeBSD-SA-16:11.openssl
-----BEGIN PGP SIGNED MESSAGE----- Hash: SHA512 ============================================================================= FreeBSD-SA-16:11.openssl Security Advisory The FreeBSD Project Topic: OpenSSL SSLv2 ciphersuite downgrade vulnerability Category: contrib Module: openssl Announced: 2016-01-30 Affects: All supported versions of FreeBSD. Corrected: 2016-01-28 21:42:10 UTC (stable/10, 10.2-STABLE) 2016-01-30 06:12:03 UTC (releng/10.2, 10.2-RELEASE-p12) 2016-01-30 06:12:03 UTC (releng/10.1, 10.1-RELEASE-p29) 2016-01-30 06:09:38 UTC (stable/9, 9.3-STABLE) 2016-01-30 06:12:03 UTC (releng/9.3, 9.3-RELEASE-p36) CVE Name: CVE-2015-3197 For general information regarding FreeBSD Security Advisories, including descriptions of the fields above, security branches, and the following sections, please visit . I. Background FreeBSD includes software from the OpenSSL Project. The OpenSSL Project is a collaborative effort to develop a robust, commercial-grade, full-featured Open Source toolkit implementing the Secure Sockets Layer (SSL v2/v3) and Transport Layer Security (TLS v1) protocols as well as a full-strength general purpose cryptography library. II. Problem Description A malicious client can negotiate SSLv2 ciphers that have been disabled on the server and complete SSLv2 handshakes even if all SSLv2 ciphers have been disabled, provided that the SSLv2 protocol was not also disabled via SSL_OP_NO_SSLv2. III. Impact An active MITM attacker may be able to force a protocol downgrade to SSLv2, which is a flawed protocol and intercept the communication between client and server. IV. Workaround No workaround is available, but only applications that do not explicitly disable SSLv2 are affected. To determine if a server have SSLv2 enabled, a system administrator can use the following command: % openssl s_client -ssl2 -connect : &1 | grep DONE which will print "DONE" if and only if SSLv2 is enabled. Note that this check will not work for services that uses STARTTLS or DTLS. V. Solution Perform one of the following: 1) Upgrade your vulnerable system to a supported FreeBSD stable or release / security branch (releng) dated after the correction date. Restart all deamons using the library, or reboot the system. 2) To update your vulnerable system via a binary patch: Systems running a RELEASE version of FreeBSD on the i386 or amd64 platforms can be updated via the freebsd-update(8) utility: # freebsd-update fetch # freebsd-update install Restart all deamons using the library, or reboot the system. 3) To update your vulnerable system via a source code patch: The following patches have been verified to apply to the applicable FreeBSD release branches. a) Download the relevant patch from the location below, and verify the detached PGP signature using your PGP utility. [FreeBSD 10.2] # fetch https://security.FreeBSD.org/patches/SA-16:11/openssl-10.2.patch # fetch https://security.FreeBSD.org/patches/SA-16:11/openssl-10.2.patch.asc # gpg --verify openssl-10.2.patch.asc [FreeBSD 10.1] # fetch https://security.FreeBSD.org/patches/SA-16:11/openssl-10.1.patch # fetch https://security.FreeBSD.org/patches/SA-16:11/openssl-10.1.patch.asc # gpg --verify openssl-10.1.patch.asc [FreeBSD 9.3] # fetch https://security.FreeBSD.org/patches/SA-16:11/openssl-9.3.patch # fetch https://security.FreeBSD.org/patches/SA-16:11/openssl-9.3.patch.asc # gpg --verify openssl-9.3.patch.asc b) Apply the patch. Execute the following commands as root: # cd /usr/src # patch < /path/to/patch c) Recompile the operating system using buildworld and installworld as described in . Restart all deamons using the library, or reboot the system. VI. Correction details The following list contains the correction revision numbers for each affected branch. Branch/path Revision - ------------------------------------------------------------------------- stable/9/ r295060 releng/9.3/ r295061 stable/10/ r295016 releng/10.1/ r295061 releng/10.2/ r295061 - ------------------------------------------------------------------------- To see which files were modified by a particular revision, run the following command, replacing NNNNNN with the revision number, on a machine with Subversion installed: # svn diff -cNNNNNN --summarize svn://svn.freebsd.org/base Or visit the following URL, replacing NNNNNN with the revision number: VII. References The latest revision of this advisory is available at -----BEGIN PGP SIGNATURE----- Version: GnuPG v2.1.8 (FreeBSD) iQIcBAEBCgAGBQJWrFhQAAoJEO1n7NZdz2rnzcwQAJJQvYkvHuVHHBHCuV576ceJ 39Ry8ooGsNquyThUndbDYOV+Vhpj62XEnI+PXUgZPKENglnf+rRu0CWfCs1SqFQE EGOSsiXmBFyvJ8AMoQfiBdCoNRCBafqhY637IG8FU7WSpg8vYJO3bGCLmsgVbeoz V2kHmUtGUNSgksvOjo2O6ezc6rYc5jPrpB11mUZ8xFoBE9YhLNRpfttCajKAYy+9 t7S3tuGnleWWmnLdFj0jNJXjg38h9gG18L4kr+z/mFFWKYmFNdKuoXlpseMFD7pb LP7RipHDh0WQqtVOQtyu0x6BuijiuIlByadcHZO1MfDNXnu1UR5OEESs0EYElh8O 6mR/i3MZ1m9DoIoRcR1eCNQN2NiWV4tVCflSTi2pUl3TTCBpYn+THMi17c4IzTNA kaMR7AUeXgJVAntfmAx4mdqdjTam2EfCNRoMS3WdfVCD8cZQDewxFmEY2FbHUzix WUBVTUzx2BTUQO7PKJ6UdEiojetJ+OmwlaAb8WfGQTypANKUfMcyXzfmtmM4dgJg NjNIUxA9T3unmWUg5nh7CACJVWcykyM1ORLqFTrrxAlIz3d1gPI2kqGiMGtEMbzI A42xSFfHVvUJ6MzXe98Sf6cDWs98qQBTLDxHo5COpq6zV4AFDqlvdyzcJ/SQTAfq tsPAVgWspt40dxnRQfku =DN5y -----END PGP SIGNATURE-----