Spam levels reached nineteen month high as image spams continue to flood emails.
This is the highlight of the MessageLabs April 2009 report released this week.
The report noted that with image spams making a comeback, spam levels were 85.3% in April, an increase of 9.6% over the previous month. During April, there were also 3,561 new sites blocked per day, an increase of 27.3% since March.
Image spam peaked in 2007 with emails containing image attachments, such as .gif or .jpg, said MessageLabs. These images contained text that had been rendered as an image to evade traditional spam filtering techniques that would attempt to analyze word patterns in the email.
A disturbing development among image spams, according to MessageLabs, is that the images are now being hosted on what appear to be trustworth hosting sites. With the use of redirection links from reputable sites in order to mask the true location of the image hosting, spammers are able to evade spam filters that examine the domains of the hyperlinks contained in the email.
Based on the analysis of MessageLabs, the spams contain the standard email text such as unsubscribe opt-outs and privacy links, designed to make the overall appearance seem legitimate and compliant with anti-spamming legislation.
The MessageLabs latest intelligence report also noted that the recent G20 summit held in London was the subject of a number of targeted Trojan attacks during March and April.
The attacks comprised of emails which included a PDF attachment which if opened would cause a Trojan downloader to be installed and executed. This would then download further spyware components onto the targeted computer.