Filtering Spam Email with Flexible Preprocessors

Spam email is the common name for “unsolicited bulk email.” It is one of the cybernuisances we have to put up with everyday. Spam email does not just waste resources; it also poses a serious security threat. There are two types of spam email: unsolicited commercial email and email used as a delivery agent for malware (malicious software). The former uses email for commercial advertisement purposes, including illegal commercial activities. Dealing with it costs staff time and IT resources. The latter has a more sinister intention. Any type of malware, be it virus, worm, or spyware, has to find a way to infect host computers. An easy and effective way to deliver malware is through unsolicited bulk email. In the last couple of years, several high profile and successful virus/worm attacks were delivered via unsolicited bulk email—for example, LoveBug, Slammer, etc.