05/27/2009 - Anew monthly cybersecurity report from a Web security firmsays that 90.4 percent of all e-mail sent from April 28 through May 26 was spam.

This means that one out of every 1.1 e-mail messages sent is spam. All told, spam increased 5.1 percent over April, according to Symantec's  May 2009 MessageLabs Intelligence Report.

Spammers have increasingly turned to social networking Web sites to get around anti-spam countermeasures, the report notes. People who receive spam from social networking Web sites get a message that comes with a headline and a hyperlink to a legitimate social networking page.

The benefit to the spammers of using such accounts is that the emails are sent from valid accounts on major free-webmail hosting providers, which in turn means that the headers were correct for the domains from which each message originated. The emails were not being spoofed, as was often the case for these types of domains in the past. Techniques to check the validity of these headers are ineffective as anti-spam countermeasures, as all they will establish is that the sender is genuine and not spoofed or sent from a botnet.

Over a seven-day period, MessageLabs also analyzed when spam hit users and its data suggests that spammers primarily work U.S. hours and may be mostly American themselves. Most spam is received by U.S. recipients between 9 a.m. and 10 a.m local time while Europeans experience steady spam levels all day and people from the Asia-Pacific region wake up with their e-mail accounts full of spam.

♦  Graph: Symantec’s May 2009 MessageLabs Intelligence Report

Breaking the numbers down by region, Message Labs reports that spam originated from the Americas 34.8 percent of the time, followed by Europe, 31.6 percent, and Asia, 27.8 percent, of the time. More than half of all the spam analyzed in the May report came from known botnets, or armies of zombie computers directed to do a certain task, such as spread spam or steal personal information.

Here are other noteworthy trends MessageLabs identified in its May report

• Viruses - One in 317.8 emails in May contained malware (a decrease of 0.01% since April)

• Phishing – One in 404.7 emails comprised a phishing attack (an increase of 0.11% since April)

• Malicious websites – 1,149 new sites blocked per day (a decrease of 67.7% since April)