According to the FBI, it is called DNSChanger. The bureau arrested six people last year for using the malware, which is strong enough to wipe out anti-virus software and cause mass Internet outages. The FBI created a safety net to combat the problem, but they plan to take it down, which is why there is fear.
The FBI says the malware could be on your computer without any signs of it being present. To check your computer's status, click here.