by Robert McMillan, IDG News Service 

Junk images are being used to trick e-mail filters, security vendors say. 

Spam is again on the rise, led by a flood of junk images that spammers have crafted over the past few months to trick e-mail filters, according to security vendors.

Called “image-based” spam, these junk images typically do not contain any text, making it harder for filters that look for known URLs or suspicious words to block them.

Instead of a typed message, users will see only an embedded .gif or .jpeg image file urging them to buy pharmaceuticals or invest in penny stocks.

Antispam vendor Cloudmark says that half of incoming spam on the “honeypot” systems it puts out on the Internet to lure spammers is now image-based. “About a year-and-a-half ago we started seeing a little bit of it, but it wasn’t until the past six months that it became a serious issue for many antispam companies,” said Adam O’Donnell, a senior research scientist with the company.

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