Network Security guide for the home or small business network – Part 11 – Why?
Alright, so you’re still reading this series and you’re thinking. Look, I’m not protecting national security secrets. All I’m doing is (running a business|emailing my grandkids|using the web for research).
True, good point. You’re not at the defense department. OK. Let’s say you just use your computer for email and web browsing. That’s low priority stuff right? No sensitive information on your PC? Do you ever do banking online? Yes – then you should be concerned… No? You should still be concerned… here’s why…
Let’s say you browse the web and you do get a trojan or backdoor program on your machine. Let’s say it comes from a 2 year old web browser vulnerability that you didn’t know about and haven’t updated for because you’ve never heard of Windows update. What’s the worst that could happen? Well, there are a couple paths. First, likely you will get more and more “stuff” on your pc. One backdoor is enough to open the floodgates for more software. With some classes of software they certainly use the “bring a friend” strategy to infesting a system. Sometimes it’s their 20 closest friends.
Among the side effects are likely more junk mail for you and those on your contact lists, more popups, slower computer performance, more off-the-wall strange computer errors. But why would they want my pc?
There is a great value to spammers to have access to a pc to send out mail. Open relays (mail servers that allow anyone to send mail through) are getting harder to find, most ISP’s are going to catch and suspend bulk spammers, so… their current refuge is home/broadband pc’s for the most part. Another use that these pc’s are put to is in the serving of illicit/illegal files. Let’s say you had made a copy of software to distribute to your “friends”. Let’s say that software license made what you’re doing illegal. (Say it was a copy of Windows XP). You wouldn’t be able to host it just anywhere, you wouldn’t want to host it on your own server and risk being caught, you’d want to shift the blame (and location) to someone that didn’t know any better. There is a great deal of illegal content hosted this way, from cracked software (warez), to child pornography, even phishing sites can be hosted this way.
There is another way cracked PC’s can be of value. One machine visiting a web site can be a normal request for information. 10,000 PC’s visiting a web site at the same time can result in a Denial of Service for other users. Sometimes that’s by accident (serendipity?), maybe a popular tv show or broadcast mentions a websites address. Within minutes thousands of people try to visit and none of them can get the page, the server is overwhelmed with requests. In a distributed Denial of Service attack, multiple PC’s are used to make requests of a site simultaneously. Sometimes these “attacks” can last for minutes, or hours, or days. They might be against joe.nobody.com or they might be against a prominent online business, or maybe against a government computer. In fact, there’s increased involvement of organized crime, offering “protection” for businesses and those that decline get DoS’ed.
Apparently these “botnets” of infected pc’s are so plentiful the price is in the single to double figure $$’s for thousands of infected pcs.
Here’s one more reason for you to think on. Your either part of the problem or part of the solution. When your PC is hooked up to the internet you can either try to secure it and deny spammers/crackers/etc. a haven, or you can blissfully ignore it and you will likely be a part of the problem. So, even if you “don’t do anything with your computer” but email, I think you can find good arguments to be concerned about computer/network security.