Learning the ins and outs of every security issue and tweaking every setting for the optimal combination of security and convenience can take quite some time. A good way to get started is to spend a few minutes performing the following seven tasks, which address some of the most common and egregious security problems with a default installation of Mac OS X. I provide only basic instructions here; future chapters include more detailed background information and additional options.
As security vulnerabilities and other bugs are discovered in Mac OS X, Apple releases software updates to fix them. Using the very latest software is no guarantee of safety, but it significantly improves your odds. The same goes for third-party software, of course, but the software that makes up Mac OS X itself is the most crucial.
For more on software updates, see Chapter 4.
Even if you're not prepared to install Apple's latest major (paid) upgrade, you should at least download and install all the free updates available for the version of Mac OS X you're running. Of those, the most important by far are the Mac OS X updates (that is, Mac OS X 10.5.x or 10.6.x) and security updates, but updates to other software that uses the network extensively ...