What you need to know to keep Mac OS X secure

Just a few years ago, Apple commanded only a small fraction of the computer market. Today, thanks to the success of OS X and iMacs, Apple is the third largest PC maker with about an 8 percent market share. This hasn't gone unnoticed by hackers, and you can expect to see more attacks on this increasingly popular platform.

Already, a couple of instances of trojans targeting Mac users have occurred, such as a Flash-based trojan earlier this year, and another discovered in June that attempts to steal passwords and lower firewall settings.

Also, vulnerabilities in the operating system are on the rise: in 2002, there were fewer than 20 announced for the platform; in 2007 that figure surpassed 100. And this year, Apple plugged vulnerabilities in five security updates so far.