Some day they're going to get to you. Your Web site. Your company network. The portable PCs you and your employees use to work at home and on the road. As long as they're connected to the Internet or to each other, they're vulnerable. And that means your business is at risk. Thieves can steal company secrets and sensitive customer information. Or they can just break in for a thrill—and leave traces only the most careful monitoring can detect. Or none at all.

You don't have to take it. In some cases, all you need is a quick check of your company's systems to make sure they're protected with the latest security patches. Safeguarding your network and Web site is not quite as simple—but you'll sleep better at night. Here's what you need to know about the most dangerous Internet security threats—and what you can do about them now.