Why does PDO print my password when the connection fails?

Question

I have a simple website where I establish a connection to a MySQL server using PDO.

$dbh = new PDO('mysql:host=localhost;dbname=DB;port=3306',
               'USER',
               'SECRET', 
               array(PDO::MYSQL_ATTR_INIT_COMMAND => "SET NAMES utf8"));

I had some traffic on my site and the server's connection limit was reached, and the website throws this error, with my plain password in it!

Fatal error: Uncaught exception 'PDOException' with message 'SQLSTATE[08004] [1040] Too many connections' in /home/domain/html/index.php:xxx Stack trace: #0 /home/domain/html/index.php(64): PDO->__construct('mysql:host=loca...', 'USER', 'SECRET', Array) #1 {main} thrown in /home/domain/html/index.php on line 64

Ironically I switched to PDO for security reasons, so this really shocked me, because this exact error is something you can provoke very easily on most sites using simple HTTP flooding.

I have now wrapped my connection in a try/catch block, but still I think this is catastrophic!

I am new to PDO and so my question is: what do I have to do to consider to be safe? How do I establish a connection in a secure way? Are there other known security holes like this one that I have to be aware of?

Answer 1

You should have display_errors = off in your PHP.ini anyway to avoid this problem. Errors that reveal details like these come from many places, in addition to PDO.

Yes, you should also have it in a try/catch block.

You can also $pdo->setAttribute(PDO::ERRMODE_SILENT), but then you need to be checking the error codes manually rather than using a try/catch block. See http://php.net/manual/en/pdo.setattribute.php for more error constants.