The popularity and spread of broadband has added a new dimension to the old problem of malicious software. Because a broadband connection is “always on”, it is easier for an attacker to mount a sustained assault on your computer, systematically probing it for weaknesses and vulnerabilities.

Many broadband connections use “static addresses” (i.e. they always have the same IP address), so that even if the computer is turned off for a while, the attacker can resume when it reconnects knowing that it is the same computer & software. So the attacker can probe your computer in short bursts over a long period of time, and know that if broken into, they can return to the same computer over and again, either to search for changing information, or to use it to launch attacks towards other computers.

In this chapter, we'll take a look at some of the types of attack that your computer might be subjected to, and some ways of dealing with these threats.