MySQL and Mac

Question

I came across this article because I am trying to set up a database using MySQL. It explains how to set it up on your Mac but mentions "When installing MySQL, you need to be aware of the potential effect this will have on the security of your system, as a database server can open an avenue of attack." What kind on attacks are they talking about? I am a complete beginner to this and the method for optimal security installation doesn't make any sense.
http://developer.apple.com/internet/opensource/osdb.html

Answer 1

There are several different levels of security that are possible with MySQL. Depending on your installation, you may not need to worry about all of them.
If you did a default installation, with no firewall running, anyone on your local subnet could connect to your MySQL. If you are behind a NAT router (such as a Wifi router), that will be very few people. If you were directly connected to the Internet (very unusual) that would be everyone. If you don't want anyone else to connect to your MySQL, it would be best to make sure the firewall is running and that the MySQL port isn't open. (By default, most firewalls are designed to allow access to server software like MySQL. Otherwise, the server software wouldn't work! Running MySQL for your own purposes is a special case where you do want a firewall and you don't want ports open).
On another level, you can configure MySQL to handle its own security. Usually, user accounts in MySQL are configure to only allow connections from "localhost". This is a very good idea. Then, only local users, such as your self can connect. There is still a slight chance of potential vulnerability from unknown and unpatched security bugs in MySQL itself. A firewall would protect you from that infinitesimally small risk.
Finally, many people like to use the phpMyAdmin web-based admin tool. That is what most web hosting providers use so it is good to know how to use it. And it is very handy. The problem is that the firewall will allow port 80 access by default and that would give people access to your admin tool. It would be best to set the firewall to "allow only essential services". If you do want to open the web server port, make sure you have a localhost-only MySQL user account and make sure the password is good and maybe even put an htaccess file in the phpMyAdmin folder to further restrict access in any number of ways.
I think I've covered it all! Let me know if I've missed anything.