Spammers Find New Way To Clog Up Your Inbox

For solution providers, however, today's onslaught of spam spells opportunity. As more commercial e-mails manage to sneak through spam filters and into employees' inboxes, many companies are realizing they need to upgrade their antispam defenses. Their concerns are driven by spam volumes that have risen to 75 billion per day in November from 63 billion messages per day worldwide in October, with spikes as high as 85 billion per day toward the end of the month, according to security vendor IronPort, San Bruno, Calif.

One reason more Viagra sales pitches, stock tips and mortgage offers are showing up in inboxes is that spammers have been converting their advertisements from text into image format to slip them past spam filters. So far, this is working well for the spammers: So-called image spam has doubled over the past year and now accounts for about one-third of daily worldwide spam message volume, according to research from Trend Micro.

"I think people grossly underestimated just how big the image spam problem was going to get," said Tom MacArthur, principal at Storbase, a Waltham, Mass.-based VAR.

To meet the challenge of neutralizing image spam and other tactics used by spammers, companies will need to upgrade to next-generation e-mail security platforms that are capable of adapting to changing threat vectors, said Greg Hanchin, a principal at DirSec, a security integrator in Denver. "It's more important than ever for solution providers to be aligned with the right vendors," he said.

Image spam is becoming a major problem for spam filtering programs, which now need more time and processing power to determine whether an e-mail is spam, said Bill Stearns, an incident handler at the SANS Internet Storm Center. "Image spam is the forefront of spammer technology right now. If you put text into an image, it's much harder for filters to figure out if it's spam," he said.

Of the 190,000 images Stearns has been working with in his spam research efforts, 42 percent are related to so called pump-and-dump stock scams, 27 percent are pill advertisements, 11 percent are hawking deals on Rolex watches, and 7 percent are mortgage offers.

Meanwhile, so-called botnets, or legions of compromised, remotely controlled PCs, have become spammers' favorite tool for sending out large quantities of commercial e-mail. The ever-growing stealth and sophistication of botnet technology makes them effective as image spam conduits because they're difficult to detect, Stearns said. The use of botnets for spam also highlights spammers' shift away from channeling commercial e-mail through SMTP servers, a fact that was underscored by the December shuttering of the Open Relay Database, a nonprofit effort to collect and blacklist IP addresses of verified open SMTP relays.

Solution providers believe vendors that don't tailor their product portfolios to counteract spammers' ingenuity risk getting left behind. "Image spam is going to drive a huge amount of business for us. It definitely will cause demand for new products because legacy antispam systems are just not going to work at stopping it," said Stephen Nacci, regional account manager at TLIC Worldwide, Wakefield, R.I.