This week the proportion of image spam attracted to our spam honeypots reached a new high of 48.9%. In fact, it was so high that it went off the scale on our image spam gauge. Now, almost every other spam message is image spam. The phenomenon is continuing to cause headaches for ISPs and email administrators everywhere. The rise suggests continuing success by spammers in using image spam techniques in getting their message through anti-spam filters.
While many anti-spam vendors are scrambling for new technology to combat this threat, the MailMarshal SpamCensor is maintaining a very respectable detection rate of 99.7% against image spam, averaged over the last two months. Why the good result? The reason is that the SpamCensor looks for many different patterns or spam ‘traits’ – most of which have nothing to do with the attached image. In fact, to the SpamCensor, the image itself is almost irrelevant.