OS X has a spectacular reputation for stability and security. At this writing, there still hasn’t been a single widespread OS X virus—a spectacular feature that makes Windows look like a waste of time. There’s also no Windows-esque plague of spyware (downloaded programs that do something sneaky behind your back).
The usual rap is, “Well, that’s because Windows is a much bigger target. What virus writer is going to waste his time on a computer with 8 percent market share?”
That may be part of the reason OS X is virus-free. But OS X was also built more intelligently from the ground up. Listed below are a few of the many drafty corners of a typical operating system that Apple has solidly plugged:
The original Windows XP came with five of its ports open. OS X has always come from the factory with all of them shut and locked.
Ports are channels that remote computers use to connect to services on your computer: one for instant messaging, one for Windows’ remote-control feature, and so on. It’s fine to have them open if you’re expecting visitors. But if you’ve got an open port that exposes the soft underbelly of your computer without your knowledge, you’re in for a world of hurt. Open ports are precisely what permitted viruses like Blaster to infiltrate millions of PCs. (Microsoft finally closed those ports in Windows XP Service Pack 2.)
In OS X, no program (like a virus) can install itself without your awareness. You’re notified at every juncture when anything is ...