Spam continues surge as spammers become clever in 2007

Spammers continued to send a barrage of unwanted messages in 2007, developing new ways to sneak by antispam software and clog company servers.

Security researchers say that as long as spam continues to be a profitable business, the most sophisticated spam filters and other antispam technologies will continue to be thwarted by spam gangs.

Last year saw a growing number of sophisticated messages including image spam, designed to embed a message in the form of an image. Spam campaigns also grew more targeted tricking company executives into clicking links in messages that appeared to be legitimate.

Global spam volumes have doubled this year to 120 billion messages daily, according to Cisco Systems-owned Ironport Systems.

"We thought spammers were Einsteins because they used a different way to package up their message with just one file type," said David Mayer, an Ironport product manager.

As much as 4% of malicious activity also came from addresses from inside Fortune 100 companies, as some employee computers get turned into bots to churn out spam and malicious code, according to Symantec, which also tracks Spam and malware trends.