Email appliance vendor IronPort Systems Inc is to release data which shows that the use of a spamming technique known as “image spam” is on the rise.
Image spam tries to bypass both traditional content- and signature-analysis, and contains little or no text to analyze, but simply a .gif file with an image. Spammers hope that their unsolicited messages will slip through enterprise and ISP anti-spam filters as a result of the text and graphics mix contained in them not being easily recognized by a machine.
Results from a new study by San Bruno, California-based IronPort shows that the use of image-based spam has exploded, growing from less than 1% of all spam in June of 2005 to more than 15% of all spam in June 2006.
Earlier in June, CipherTrust Inc also reported an upward nudge in the appearance of image spam, something it said may be a result either of increased use of the technique, or simply something that is in line with the increase in spam overall.
IronPort produces various internet security threat reports based on data gathered by its Threat Operations Center and the open source SenderBase reputation database which pulls statistics from 75,000 participating networks.