Spammers fool filters with images

Posted on Thursday, Jun 29 2006 @ 00:47 CEST by Thomas De Maesschalck
Spammers are increasingly using images to fool e-mail filters, spam experts report:
The images fool some filters because they have no easy way of knowing whether a graphical file contains an innocent photograph of a friend's birthday party or embedded text pitching Viagra or a company's stock.

The development marks yet another escalation in the battle between spammers and filter developers: As software gets smarter at detecting junk, spammers get smarter at fooling the filters.

Until last year, the use of image spam has been in decline as anti-spam filters figured out how to detect it often by applying a mathematical formula to known spam images and generating a unique signature that software can use to flag junk, said Craig Sprosts, senior product manager for anti-spam vendor IronPort Systems Inc.

But earlier this year, tools began circulating among spammers to automatically vary images ever so slightly a change in color here, a slightly larger border there. That changes the signature, helping it escape detection.
More details over here.

About the Author

Thomas De Maesschalck

Thomas has been messing with computer since early childhood and firmly believes the Internet is the best thing since sliced bread. Enjoys playing with new tech, is fascinated by science, and passionate about financial markets. When not behind a computer, he can be found with running shoes on or lifting heavy weights in the weight room.

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