Date: Thu, 30 Apr 2015 11:50:25 -0400 From: Jon Oberheide <jon@...rheide.org> To: oss-security@...ts.openwall.com Cc: ocert-announce@...ts.ocert.org, bugtraq@...urityfocus.com Subject: Re: [oCERT-2015-003] MySQL SSL/TLS downgrade Some additional silly links related to the vulnerability: http://backronym.fail/ https://www.duosecurity.com/blog/backronym-mysql-vulnerability And actually one useful link from Todd Farmer: http://mysqlblog.fivefarmers.com/2015/04/29/ssltls-in-5-6-and-5-5-ocert-advisory/ On Wed, Apr 29, 2015 at 10:00 AM, Andrea Barisani <lcars@...rt.org> wrote: > > #2015-003 MySQL SSL/TLS downgrade > > Description: > > The MySQL project is an open source relational database management system. > > A vulnerability has been reported concerning the impossibility for MySQL > users > (with any major stable version) to enforce an effective SSL/TLS connection > that would be immune from man-in-the-middle (MITM) attacks performing a > malicious downgrade. > > While the issue has been addressed in MySQL preview release 5.7.3 in > December > 2013, it is perceived that the majority of MySQL users are not aware of > this > limitation and that the issue should be treated as a vulnerability. > > The vulnerability lies within the behaviour of the '--ssl' client option, > which on affected versions it is being treated as "advisory". Therefore > while > the option would attempt an SSL/TLS connection to be initiated towards a > server, it would not actually require it. This allows a MITM attack to > transparently "strip" the SSL/TLS protection. > > The issue affects the ssl client option whether used directly or triggered > automatically by the use of other ssl options ('--ssl-xxx') that imply > '--ssl'. > > Such behavior is clearly indicated in MySQL reference manual as follows: > > For the server, this option specifies that the server permits but does > not require > SSL connections. > > For a client program, this option permits but does not require the > client to > connect to the server using SSL. Therefore, this option is not > sufficient in > itself to cause an SSL connection to be used. For example, if you > specify this > option for a client program but the server has not been configured to > permit > SSL connections, an unencrypted connection is used. > > In a similar manner to the new '--ssl' option behaviour, users of the MySQL > client library (Connector/C, libmysqlclient), as of MySQL 5.7.3, can take > advantage of the MYSQL_OPT_SSL_ENFORCE option to enforce SSL/TLS > connections. > > The vulnerability also affects the MySQL forks MariaDB and Percona Server, > as > the relevant 5.7.3 patch has not been pulled, at the time of this > advisory, in > their respective stable versions. > > Affected version: > > MySQL <= 5.7.2 > > MySQl Connector/C (libmysqlclient) < 6.1.3 > > Percona Server, all versions > > MariaDB, all versions > > Fixed version: > > MySQL >= 5.7.3 > > MySQl Connector/C (libmysqlclient) >= 6.1.3 > > Percona Server, N/A > > MariaDB, N/A > > Credit: vulnerability report from Adam Goodman, Principal Security > Architect > at Duo Security. > > CVE: CVE-2015-3152 (MariaDB, Percona) > > Timeline: > > 2015-03-20: vulnerability report received > 2015-03-23: contacted Oracle Security > 2015-04-04: oCERT sets embargo date to April 29th > 2015-04-20: reporter confirms MariaDB is affected > 2015-04-22: contacted MariaDB and affected vendors, assigned CVEs > 2015-04-23: contacted Percona > 2015-04-29: advisory release > > References: > > https://github.com/mysql/mysql-server/commit/3bd5589e1a5a93f9c224badf983cd65c45215390 > http://mysqlblog.fivefarmers.com/2014/04/02/redefining-ssl-option > http://dev.mysql.com/doc/relnotes/mysql/5.7/en/news-5-7-3.html > https://mariadb.atlassian.net/browse/MDEV-7937 > https://bugs.launchpad.net/percona-server/+bug/1447527 > > Permalink: > http://www.ocert.org/advisories/ocert-2015-003.html > > -- > Andrea Barisani | Founder & Project Coordinator > oCERT | OSS Computer Security Incident Response Team > > <lcars@...rt.org> http://www.ocert.org > 0x864C9B9E 0A76 074A 02CD E989 CE7F AC3F DA47 578E 864C 9B9E > "Pluralitas non est ponenda sine necessitate" > -- Jon Oberheide <jon@...rheide.org> GnuPG Key: 4096R/52961381 Fingerprint: 964B 79EF 47D4 D7D0 CF73 D456 97FF B9D2 5296 1381
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