A San Diego company says ordinary Web sites are becoming greater targets for Internet criminals looking to corrupt users’ computers.

Dan Hubbard, vice president of security research at Websense, said Web sites “from top-tier names to mom-and-pop bakery shops” are being targeted by advertisements that take advantage of the holes in the Internet Explorer browser to implant a tiny program that communicates with a “mother ship” server, often in Russia or China, USA Today reported Wednesday.

The programs implanted by the tainted Web sites save secure form information — such as names, social security numbers and credit card information — and connects the infected computers to networks of similarly contaminated machines to produce and distribute Internet spam.

A recent study by security firm Cyveillance uncovered 50,000 corrupted pages, and Websense estimates the number could be up to 10 times that many.

“It speaks to the level of cunning and sophistication of the bad guys,” says Roger Thompson, chief technical officer of Exploit Prevention Labs.