MySQL SSL Users: BEWARE This Bug

If you’re using MySQL and SSL, you might want to glance over this article and give your setup a quick test.

I’ve uncovered an alarming bug in 5.5 where one could gain access to your MySQL instance just knowing the username and password (not having any SSL certificate, key, etc.)!

Of course, I’ve filed a bug about it here:

http://bugs.mysql.com/bug.php?id=62743

It’s been over 4 days now, and not one comment from the MySQL Bug/Dev Team.

So once again, I feel the need to share this bug with the public, in case you are using SSL with 5.5, and think your connections are secure, or that only users with the certs/key could gain access.

For SSL Users, you’ll already have this set up, but for those who don’t, I’ve simply got mysqld (5.5.15 and 5.5.16 thus far) running with the following options:

ssl-ca	 = "C:/Program Files/MySQL/mysql-5.5.16/certs/ca-cert.pem"
ssl-cert = "C:/Program Files/MySQL/mysql-5.5.16/certs/server-cert.pem"
ssl-key	 = "C:/Program Files/MySQL/mysql-5.5.16/certs/server-key.pem"

In theory, any user connecting should either be specifying the –ssl-ca option, path, and file, or both the –ssl-cert and –ssl-key options.

However, at least in 5.5.15 and 5.5.16 (haven’t tested any others yet), one can connect with *just* the –ssl-key option.

What’s worse, and most important, is that you don’t even have to specify a file here. Just specify some bogus text!

I created 2 users, one local and one remote, using these 2 commands:

GRANT ALL PRIVILEGES ON *.* TO 'ssluser'@'localhost' IDENTIFIED BY 'ssluser' REQUIRE SSL;)
GRANT ALL PRIVILEGES ON *.* TO 'ssluser'@'remote-hostname' IDENTIFIED BY 'ssluser' REQUIRE SSL;

Now, just specify “buggg” for the -ssl-key option (no path, no file, no nothing):

mysql -ussluser -pssluser -P3430 --ssl-key=buggg

Voila!

The user connects as if it were using an SSL connection. All that was needed to connect to this remote host is the username and password.

Check out the output:

Localhost:

C:\Program Files\MySQL\mysql-5.5.16\bin>mysql -ussluser -pssluser -P3430 --ssl-key=buggg
Welcome to the MySQL monitor.  Commands end with ; or \g.
Your MySQL connection id is 11
Server version: 5.5.16-log MySQL Community Server (GPL)

Copyright (c) 2000, 2011, Oracle and/or its affiliates. All rights reserved.

Oracle is a registered trademark of Oracle Corporation and/or its
affiliates. Other names may be trademarks of their respective
owners.

Type 'help;' or '\h' for help. Type '\c' to clear the current input statement.

mysql> status
--------------
mysql  Ver 14.14 Distrib 5.5.16, for Win32 (x86)

Connection id:          11
Current database:
Current user:           ssluser@localhost
SSL:                    Cipher in use is DHE-RSA-AES256-SHA
Using delimiter:        ;
Server version:         5.5.16-log MySQL Community Server (GPL)
Protocol version:       10
Connection:             localhost via TCP/IP
Server characterset:    latin1
Db     characterset:    latin1
Client characterset:    cp850
Conn.  characterset:    cp850
TCP port:               3430
Uptime:                 35 min 26 sec

Threads: 1  Questions: 24  Slow queries: 0  Opens: 33  Flush tables: 1  Open tables: 0
Queries per second avg: 0.011
--------------

Remote Host:

C:\Documents and Settings>mysql -ussluser -pssluser -h192.168.1.100 -P3430 --ssl-key=buggg
Welcome to the MySQL monitor.  Commands end with ; or \g.
Your MySQL connection id is 6
Server version: 5.5.16-log MySQL Community Server (GPL)

Type 'help;' or '\h' for help. Type '\c' to clear the buffer.

mysql> status
--------------
mysql  Ver 14.12 Distrib 5.0.70, for Win32 (ia32)

Connection id:          6
Current database:
Current user:           ssluser@HOST-LAPTOP
SSL:                    Cipher in use is DHE-RSA-AES256-SHA
Using delimiter:        ;
Server version:         5.5.16-log MySQL Community Server (GPL)
Protocol version:       10
Connection:             192.168.1.100 via TCP/IP
Server characterset:    latin1
Db     characterset:    latin1
Client characterset:    latin1
Conn.  characterset:    latin1
TCP port:               3430
Uptime:                 13 min 13 sec

Threads: 2  Questions: 14  Slow queries: 0  Opens: 33  Flush tables: 1 Open tab
les: 26  Queries per second avg: 0.017
--------------

Again, I have no idea how many versions are affected by this yet. I’ve only tested 5.5.15 and 5.5.16 (seen on both Windows and Linux, as well).

In fact, that’s all I thought I would have needed to test, as I thought MySQL would have been all over this bug. But since there’s been no word from them about it, I feel it’s my duty to let the community know about this bug until it gets fixed.

(And I even wonder if the above is secure or not. I mean, it “says” the cipher is in use, but since I didn’t specify a ssl cert or key, how can I be certain this is secure.)