Thousands in US could be blocked from Internet access

In November, the FBI arrested six Estonian hackers accused of running an Internet fraud ring that infected approximately 4 million computers in more than 100 countries, including about 500,000 in the United States.

The malware, called DNSChanger Trojan, hijacks computers when users type a Web address in their Internet browser and manipulates their Web activity. The FBI reported that the hackers generated at least $14 million in illicit fees related to online advertising.

The international cyber ring was dismantled and its servers were shut down. The FBI subsequently had a private company run identical servers for four months in an effort to help get infected computers cleaned.

That arrangement ends Thursday, and computers still infected then might not be able to get on the Web on March 9.