A new wave of spam could be on the way that tricks recipients by looking like itís a message sent from their friends' e-mail address. This sort of spam would bypass even those filters that currently weed out 99% of the bad stuff, says John Aycock, an assistant professor of computer science at the University of Calgary.
Aycock and student Nathan Friess conducted research and wrote a paper dubbed "Spam Zombies from Outer Space" to show that generating such customized spam -- such as in the form of e-mail replies -- would not be too difficult, as has been assumed in the past. Spammers have leaned toward bulk e-mail generation that is less customized.
More information can be found here.