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.
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.
"It's clear that activity is now being pointed toward more commercial type behavior," Zulfikar Ramzan, a senior principal researcher at Symantec.
Symantec's spam figures reflect Ironport's figures, showing a 50% increase in activity over 2006. Ramzan said Symantec also tracked botnets, spam activity, zombies and other internet attacks from within some large enterprises. It's a serious threat, Ramzan said because people using the machines either are not using good computer practices or are doing malicious activity from within the enterprise themselves.
Authorities also began a massive crackdown against spammers in 2007. In May, police arrested Robert Alan Soloway, after years of investigations. He was accused of using botnets to send out millions of spam emails. In all, eight people had been indicted, pleaded guilty or been sentenced for botnet crimes. Spam dipped slightly after his arrest, according to figures provided by Symantec, but any improvements were short lived as spam levels reached and even exceeded levels prior to his arrest.
The FBI launched a second crackdown in November, serving 13 search warrants in the U.S. and by overseas law enforcement partners in connection with the operation.
Botnet sophistication also continued to increase contributing to the rising wave of spam. Alex Shipp, an antivirus technologist for email/IM security vendor, MessageLabs, and told SearchSecurity.com that criminal spam rings are using them to spew malware laced spam.
"Coders are becoming smarter and they're becoming much more difficult to detect," Shipp said.
The family of malware known as Storm, Peacomm and Nuwar morphed in 2007 to be the most resilient and adaptive malicious programs in recent years. Security researchers believe Storm is well into the millions of machines, with some estimates going as high as 50 million infected PCs.
In June, Storm was tweaked to generate PDF files to escape detection from antivirus software and trick employees with emails that look like business letters. The PDF campaign was short lived however, as spammers turned to more profitable methods to dupe employees.
Don't expect any let up in Spam in 2008. Already, Symantec has started seeing the first examples of spam connected to the 2008 Olympics in Beijing, China.
As spammers grow increasingly sophisticated, they will continue to play a cat and mouse game with security vendors, experts say. A technology or method that defeats all spam, is not likely to be a reality in the near future.