Watch out, the Riddle vulnerability affects some Oracle MySQL versions. Update them now

Pierluigi Paganini April 15, 2017

A bug dubbed Riddle vulnerability affecting MySQL 5.5 and 5.6 clients exposed user credentials to MiTM attacks. Update to version 5.7.

A coding error dubbed The Riddle has been uncovered in the popular DBMS Oracle MySQL, the issue can be potentially exploited by attacker powering a man-in-the-middle attack to steal usernames and passwords.

“The Riddle is a critical security vulnerability found in Oracle’s MySQL 5.5 and 5.6 client database libraries. The vulnerability allows an attacker to use riddle in the middle for breaking SSL configured connection between MySQL client and server.” states the description of the flaw.“This vulnerability is a very critical security hole because it affects MySQL — a very popular SQL database — and SSL connection which is by its definition secure.”

The flaw, tracked as CVE-2017-3305, potentially exposes login credentials to eavesdropping, an attacker can capture them when a MySQL clients 5.5 and 5.6 send them to servers.
A security update released for the versions 5.5.49 and 5.6.30 failed to completely fix the bug. The experts noticed that the Versions 5.7 and later, as well as MariaDB systems, are not affected by this issue.

According to security researcher Pali Rohár, the Riddle vulnerability results for the failed attempt to patch the BACKRONYM vulnerability affecting the MySQL database. The Backronym vulnerability exposes passwords to attackers who are in a position to run a man-in-the-middle attack, even if the traffic is encrypted.

“Security update for the stable MySQL 5.5.49 and 5.6.30 versions consisted of adding a verification of security parameters after the authentication process was finished.” “Since it is done after the authentication, riddle in the middle attack together with SSL-downgrade attack can be used by the attacker to steal login data for immediate authentication and log into the MySQL server,” wrote Rohár.

Riddle vulnerability

“Ridiculous part is that MySQL client doesn’t report any SSL-related error when MySQL server declines to authenticate a user and instead reports unencrypted error message send by the server. Furthermore, the error message is controlled by the attacker, when the riddle in the middle attack is active.”

The expert suggests updating the client software to MySQL 5.7 or MariaDB, because the security updates for these applications correctly work.

The Riddle vulnerability was discovered in February, but today the bug still affect the Oracle MySql software.

“Reporting bugs to Oracle is useless (even those which are security related) if you are not an Oracle customer. They can perfectly ignore any reports and they would be very happy if nobody knew about it so they don’t have to fix the bugs,” explains Rohár.

“It looks like immediate public disclosure is the best responsible solution for the users, as it is the only way to protect them and let them know immediately what should be done if they are affected.”

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Pierluigi Paganini

(Security Affairs –  SQL, Riddle vulnerability)

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