Recognizing Security Threats

I’m not trying to freak you out, but I’m not exaggerating the dangers to your network security either. Here’s an example: Recently, I hooked up a friend’s computer to a high-speed network connection from his phone company. He had antivirus software but no personal firewall in place yet, and before I could get that firewall set up (which usually takes about 10 minutes), 15 virus alerts popped up!

Although viruses are common threats that we hear about all the time, there are many other nasty things out there as well. Bad guys who create threats to a network generally have one of two purposes in mind: destruction or reconnaissance. They’re seeking to destroy data or deny access, and maybe even nick information that you definitely don’t want them to have. Some types of attacks can accomplish both, but they’re usually combinations of simpler forms. In the following sections, we’ll look at several common...