Phishing is a well known way to entice you to visit a Web site that can exploit your browser and plant malware on your machine. Web content filtering isn’t enough to combat malware deployed over the Web because content filters usually analyze entire sites and not specific pages. So if malware is hosted on a hacked site or a big public site, then a content filter typically won’t stop users from visiting specific pages.

We talked about legitimate sites that have malware delivery systems in a previous blog. Here’s one of them (Sony’s U.S. PlayStation 3 site). According to Sophos (www.sophos.com) a security company who has made an effort in warning many internet users about this problem. In a recent study, 79 percent of Web sites hosting malware-infected pages were legitimate business sites.

Malware includes threats such as trojans, bots, rogues, spyware, worms, rootkits, and adware. The bot is a particularly pernicious piece of malware that is on the rise.

What are bots?

A bot is simply a program that runs automated tasks on the Internet. Not all bots are bad, but obviously the ones we are concerned with are the nasty kind. They are planted on a computer in the manner described above and used to do a whole bunch of dirty deeds, such as performing click fraud, sending spam, harvesting usernames and passwords, launching DDoS attacks, and spreading other viruses and worms.