-International hackers took control of at least 550,000 computers
-FBI takes unusual step of setting up a safety net to prevent internet disruptions
-Most victims are unaware they have been affected after using rogue servers
By DAILY MAIL REPORTER
Infected: It is estimated that a network of about 570,000 computers was targeted by hackers
Hundreds of thousands of people could lose access to the internet by July following a hackers' scam - and they don't even know it.
Unknown to most of them, their problem began when international hackers ran an online advertising scam to take control of infected computers around the world.
In a highly unusual response, the FBI set up a safety net months ago using government computers to prevent Internet disruptions for those infected users. But that system is to be shut down.
Now, the FBI is encouraging users to visit a website run by its security partner that will inform them whether they're infected and explain how to fix the problem. After July 9, infected users won't be able to connect to the Internet.
Connection timebomb: Most victims don't even know their computers have been infected, although the malicious software probably has slowed their web surfing and disabled their antivirus software, making their machines more vulnerable to other problems
Most victims don't even know their computers have been infected, although the malicious software probably has slowed their web surfing and disabled their antivirus software, making their machines more vulnerable to other problems.
Last November, the FBI and other authorities were preparing to take down a hacker ring that had been running an Internet ad scam on a massive network of infected computers.
Tom Grasso, an FBI supervisory special agent, said: 'We started to realise that we might have a little bit of a problem on our hands because ... if we just pulled the plug on their criminal infrastructure and threw everybody in jail, the victims of this were going to be without Internet service.
Rogue servers: The FBI (pictured) believes at least 568,000 users could have been affected by the hackers
'The average user would open up Internet Explorer and get `page not found' and think the Internet is broken.'
On the night of the arrests, the agency brought in Paul Vixie, chairman and founder of Internet Systems Consortium, to install two Internet servers to take the place of the truckload of impounded rogue servers that infected computers were using.
Federal officials planned to keep their servers online until March, giving everyone opportunity to clean their computers. But it wasn't enough time. A federal judge in New York extended the deadline until July.