Last year, visitors to a wide range of gambling sites started reporting unusual behavior. Strange text windows would pop up, offering users special access codes for third-party gambling sites. Links would appear with new affiliate tags, an almost unnoticeable difference that could still prove wildly lucrative for whoever got paid for the new referrals. The sites’ visitors were being hacked, but webmasters couldn’t figure out where the new scripts were coming from.
"We very carefully monitored the traffic coming from our servers because we take that sort of situation extremely seriously," says Michael Corfman, executive director of the Gambling Professional Webmasters Association, the organization targeted by the attack. "The monitoring...