If you think your computer is secure because it is a Mac, you are dead wrong. The latest patch for OS X – 10.6.8 – contains 29 patches for security holes that allowÂ arbitrary code execution. Any of those holes could be used to totally own your computer, circumventing any antivirus or encryption software you may be running. These 29 have been patched, but you can be sure there are others in the OS and in popular software like Flash and Adobe’s PDF reader.
If you want to keep a system safe, keep it physically disconnected from the internet.