MessageLabs Intelligence noted that spam levels rose above the 85% mark for the first time in nineteen months. Image spam was a phenomena that peaked in 2007, with emails containing image attachments, such as .gif or .jpg that contained the spam content. Often these images contained text that had been rendered as an image to evade traditional spam filtering techniques that would attempt to analyse the patterns of words in the emails.
Fast-forward to the present day and these images are now being hosted on what appear to be trustworthy hosting sites, whilst taking advantage of redirection links from reputable sites in order to obfuscate the true location of the image hosting. This is also a technique employed by spammers to evade spam filters that examine the domains of the hyperlinks contained in the email, in order to make a judgment about the nature of that domain and the likelihood that it is a spam message.
MessageLabs: Spam levels up to 85.3 percent last month
Posted on Tuesday, May 05 2009 @ 07:25 CEST by Thomas De Maesschalck
MessageLabs claims spam levels rose to 85.3 percent of all e-mail messages in April, an increase of 9.6 percent since March. The security firm says a return of image spam pushed spam levels above 85 percent for the first time since September 2007. The report also mentions one in 304.9 e-mails contains malware, and one in 404.7 e-mails comprises a phishing attack.