Monday, 20 November 2006

Image Spam Rates Quintuple in 2006

IronPort Threat Operation Centre has seen a more than 67 per cent increase in overall spam volume and a 500 per cent increase in image spam since August this year. This increase is attributed to a number of trends, including a significant uptake in the number of penny stock promotions that has been hitting the millions of inboxes of its more than 35,000 customers worldwide.

According to IronPort's statistics, worldwide spam levels in October 2005 were 31 billion messages per day. That figure has risen to 61 billion messages per day in 2006. Twenty-five per cent of this spam was image-based, compared to 4.8 per cent the year before. The average message size also increased from 8.9KB to 13KB. Global spam contributed to more than 819TB of bandwidth per day during 2006.

IronPort squarely laid the blame on the falling "catch rates" of spam on signature-based antivirus solutions. IronPort marketing vice president Tom Gillis said rapidly changing randomisation techniques, the basis of image spam, are counteracting signature-based tools.

Adam Biviano, Trend Micro premium services manager said, "Image-based spam is definitely one of the techniques employed to get around legacy technologies, which is why spam filters look at more than image content for traffic patterns associated with sources and use reputation databases. "A combination of technology needs to be used because the spammers know how to get around some products."

"Image-based spam has created problems for many solutions that do not have the comprehensive feature set needed to protect against it," said Stephen Pao, vice president of product management for Barracuda Networks.