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What's with all this spam?

Unwanted e-mail levels 'shot up like crazy'; image spam partly to blame, say experts.

By , Network World
November 08, 2006 07:19 PM ET

Network World - Researchers and IT managers are confirming security vendors’ claims that spam levels have spiked in the past month – some say by as much as 80 % -- and show no signs of decreasing.

“There are enormous amounts of spam; it’s shot up like crazy since the beginning of October,” says John Levine, president of consulting firm Taughannock Networks and co-chair of the Internet Research Task Force's Anti-Spam Research Group, who operates a number of e-mail addresses that aren’t filtered for spam. “Earlier this year I was seeing about 50,000 spam messages a day, now I’m seeing 100,000.”

Levine’s assumption is this spike in spam levels is a result of a new generation of viruses and zombies that can infect PCs more quickly and are harder to get rid of. In its October report, messaging security vendor MessageLabs says the spike is largely due to two Trojan programs, Warezov and SpamThru.

Others say a new breed of spam messages called image spam -- messages with text embedded in an image file that evade spam filters, which can’t recognize the words inside the image -- is responsible.

At North Shore-LIJ Heath System, a network of hospitals based in Great Neck, N.Y., with about 12,000 e-mail users, there’s been an 80% increase in spam received in the last 45 days, says system architect Steve Young, and most of it is image spam.

“We got slammed with a 50% increase [in spam] in one day. For the past year-and-a-half none of my users ever got a spam message; in that first 48 hours [of image-spam blasts] there were 500 calls and over 1,000 complaints from users,” he says.

The majority of these image spam messages are so-called pump and dump scams, where spammers purchase a penny stock, promote it through e-mail, then sell it at a profit. Most appear to come from Europe, says Young.

After receiving so many calls from his users Young called BorderWare, his e-mail security vendor, to ask for help. The company enrolled him in a beta program for its new technology designed to block image spam, which Young says is working. “We blocked 7,000 image spam messages in the first day” of trialing the new technology.

What’s made image spam so vexing is that spammers have learned to represent words in an image that are recognizable to the human eye because of the way people recognize images that a computer can’t understand, says Andrew Graydon, CTO of BorderWare.

“They’re banking on eye recognition, and so many of the solutions out there only deal with text analysis,” says Graydon. The company’s new technology, set to be unveiled next week, analyzes image spam and comes up with a characterization of the message that tracks 30 different pieces of information about it that mimic the way people visualize.

Of course, as vendors come up with new techniques, spammers do, too. Image spam began popping up a few months ago, and security vendors responded with products that create a “fingerprint” of the message and match that against new incoming messages. Then spammers began randomizing image spam so that each message was slightly different from the last, therefore evading fingerprinting technology.

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