Fortunately, the agency said, users can clean their computer of the suspected malware program in question with a few clicks and a visit to a diagnostic Web site.
Six Estonian nationals were arrested in November after a two-year FBI probe called Operation Ghost Click, and accused of infecting computers worldwide with malware called DNS Changer, which opened up the computers to viruses, CNN reported Monday.
The virus directed users to alleged criminals' own servers and allowed the scammers to manipulate online advertising, racking up more than $14 million in illegal income, the FBI said.
"They were organized and operating as a traditional business but profiting illegally as the result of the malware," the FBI said in a release. "There was a level of complexity here that we haven't seen before."
About 350,000 computers are infected, including 85,000 in the United States, the FBI estimated.
A Web site, http://www.dcwg.org, has been created, where users can see whether they've been infected by the malware, the agency said.