Broadband-connected computers commandeered by spammers drove a 30% increase in the amount of spam headed to consumer e-mail boxes and corporate networks, an e-mail security firm says. Remotely controlled armies of computers, called zombies, spread to all regions of the world in 2006, with as many as 8 million computers spewing billions of junk e-mails on any given day, Commtouch said Wednesday in its 2006 Spam Trends Report.
New sophisticated spamming techniques overcame traditional anti-spam methods, such as content filtering, heuristics, and IP address blacklisting, the report said. Among the more effective new techniques was the use of image-based spam, which is much harder for security software to detect than text-based spam. The former accounted for 70% of the bandwidth taken up by spam this year, Commtouch said. "Spam outbreaks got bigger, faster, and smarter during 2006," said Amir Lev, Commtouch president and chief technology officer, in a statement.