In this chapter, we hope we've given you a good picture of the people you're up againstsome of whom aren't even actually your enemies, but who can still do plenty of damage to your system if you don't take precautions to protect it against their actions. As we've repeated with other security topics, it's important to think about these things in terms of the worst possible scenario. Some people might think that you're being overly paranoid; others might think that you've taken a very negative stance toward other computer users and the threats they create. You have a choice between listening to themhaving your system be vulnerable and being part of the larger problemand working to limit the vulnerabilities and to protect your and their interests in spite of their protestations. Don't let the fact that it's a naturally distasteful thing to think the worst of your (and other computer systems') users get in the way of your need to consider what might be done to your machine. It is people, not evil computers, that are behind attacks on computers. If you refuse to consider the source of the violence because it's distasteful, you'll be in the same boat as a host of other misguided individuals and groups who refuse to focus on the human causes of any number of other forms of violence. It's not a good boat to be in. There are evil people out there, and they'll do evil things, using whatever tools are at their disposal. If you're not prepared, they might do them to you.
As with all areas of computer security, you can probably eliminate 90% of the likely threats to your system with little effort beyond conscientiously keeping up with patches to the systems that have been found to be vulnerable.