So-called "image spam" is on the rise once again -- as clever hackers try to sneak by spam screening software that tests messages for spam based on keywords.
After declining steadily throughout 2005 -- from about 12 percent ofall spam at the beginning of the year, down to about 5 percent inNovember -- the use of image spam jumped dramatically in December 2005,to 25 percent of all spam. It has remained at that level fairlyconsistently for the last six months, according to Postini, a messagingmanagement company based in San Carlos, Calif.
To be sure, up-to-date spam filters, like the patented PTIN technology,can detect and block image spam based on other attributes of thesending computer, message envelope and headers.There are other, emerging threats too -- like VoIP spam scams.Scammers pretending to be banks e-mail people and ask them to dial atelephone number, then enter the personal information needed to gainaccess to their finances. These fake VoIP services are reducing thecosts associated with conducting such attacks, providing theperpetrators with a lower risk of discovery.
"Postini attributes this increase to spammerstesting the deliverability of image spam in early 2005 and realizingthat many older spam filters are helpless when messages contain text toanalyze, so the use of images helps get their spam delivered," saidPostini spokesperson Catherine Leahy. "Upon seeing the positiveresults, they converted much of their spam to image spam."
These attacks are "highly sophisticated,targeted, transient and dynamic, thereby making it far more difficultto uncover and capture the perpetrators," according to Dr. JoseNazario, a senior security engineer and member of the Arbor SecurityEngineering & Response Team (ASERT) at Arbor Networks, a networksecurity leader for global business networks.
News source: Tech News World
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