A 'malicious' worm targeting users of Microsoft Windows 2000 operating system has affected computer systems in Asia and the US, including that on Capitol Hill and leading media organisations.
Microsoft said in a statement that it was 'actively' investigating news report of a malicious worm identified as 'Worm_Rbot.CEO
The worm affected computers at the US cable news network CNN, The New York Times and ABC television network.
A small number of computers in an administrative office at San Francisco International Airport also crashed, but they were not essential to the airport's operation, spokesman Mike McCarron said.
The worm repeatedly rebooted the computers, which could make them vulnerable to potential attackers but FBI said it does not appear to be a widespread attack.
The worm affects primarily Windows 2000 but it also can affect some early versions of Microsoft XP, said Johannes Ullrich, chief technology officer of the Sans Institute, a network security firm based in Jacksonville, Florida, was quoted in media reports as saying.
Lysa Myers, a virus researcher for the computer security firm McAfee, Inc., said the worm exploits a vulnerability in Microsoft's plug-and-play service.
"How it's spreading is it's looking for machines that are not patched and running itself," she said. What was causing the damage was unclear, although experts pointed to the new worm.