Washington, August 17:

Computers at several major US media firms, including The New York Times, ABC and CNN, ground to a halt from the effects of a software virus attacking an older version of Microsoft’s(MS) Windows operating system.

The virus hit late Tuesday and anchors for CNN discussed the problem on the air. Besides ABC and The New York Times, scores of companies in other sectors, such as construction equipment-maker Caterpillar, were also affected. CNN was hit at its Atlanta and New York offices and was forced to make some changes in programmes because of the disruption. The New York Times said the effects of the virus on its computers were limited. The problems appeared to have been caused by the Zotob.B virus, which was first reported on Monday. The virus targets computers running the Microasoft Windows 2000 operating system.

According to industry figures, almost 75 per cent of computers now run the newer Windows XP, which is not vulnerable to the same attack. MS released a patch for the vulnerability last week as part of its monthly security patch updates. About 10 software worms are currently making their way around the Internet, targeting the new Microsoft vulnerability, Mikko Hypponen, a spokesman for F-Secure said.

“The worms attack computers in the background, similar to how the infamous Nimda and Code Red worms operated. There’s no need to open an e-mail attachment.” With so many variants making their way around the Internet, vulnerable computers are sure to be infected,” Hypponen said, “It is pretty serious, but it only impacts some companies.”