Spammers have recently developed a new trick in their efforts to dodge spam filters. Instead of only using image spam to avoid spam filters, they have gone one step further and created animated spam. This type of spam contains gif images, making it difficult for spam filters to detect as spam.
Animated spam works by rotating various frames of pictures when displaying the e-mail message. Most of these frames are simply white backgrounds with a few pixels displayed. According to viruslist.com, the frame with the actual text will stay up on the users screen for up to 10 minutes, while the frames with small pixels can be rotated through in less than a second. These frames with the small pixels add what is known as noise to the image. This makes it difficult for spam filters to detect these e-mails as spam.
SPAMfighters filter reduces the amount of noise associated with animated spam mails, making it possible to read the coding on the spam mail easier, and filter it out. By creating a method to reduce noise in spam mails, the spam mail itself can be seen, and therefore filtered. Spammers have created animated spam mails as an attempt to create so much noise that spam filters cannot detect them and prevent them from entering users' in-boxes. Currently SPAMfighter stops at least 80 per cent of animated spam mails, and hopes to reach an almost 100 per cent detection rate in the early part of September.
Related links: (Open in a new window.)
www.spamfighter.com
Taken from Information Security Bulletin.