Ubuntu Security
Desktop Training - Ubuntu

Even with a home computer, if you're connected to the Internet, you'll want to be mindful of security. Intruders can and do break into home computer systems for various nefarious purposes. You may not have any important data for them to steal, but if they can break into your system, they can still create havoc in other ways. They could, for example, use your system as a relay to help cover their tracks while they're engaging in illegal behavior on someone else's system. Or, they could use your system to store illegal "warez" that they've stolen from elsewhere. Things can get even more ugly if they're able to obtain root privileges on your system.