ZDNet Australia first reported on Monday that a new worm called Zotob was exploiting a flaw which primarily affects the Windows 2000 platform, but has an impact on Windows XP and Windows Server 2003.
Overnight, computers across the US were hit, including those at cable news station CNN, television network ABC and The New York Times.
Trend Micro blames the havoc on various worms, including Zotob and new variants of the Rbot worm.
All of the worms exploit a security hole in the plug-and-play feature in the Windows 2000 operating system. Microsoft offered a fix for the bug as part of its monthly patching cycle last week. The software maker deemed the issue "critical," its most serious rating.
"It seems like every couple of minutes a new variant comes in. We cannot pinpoint the infections to one variant," said Joe Hartmann, director of antivirus research group at Trend Micro.
The company has seen thousands of infections from Zotob alone, Hartmann said. "We are still gathering infection reports. It is coming globally."
Mark Sinclair, technical services director at Trend Micro Australia, told ZDNet Australia this morning that although the United States was seriously affected by viruses taking advantage of the vulnerability, Australia has escaped fairly unscathed.
"We have issued a yellow [which is in the middle of its alert range] alert for a new variant of it but that is primarily because we have seen major infection in the US. I have not seen any infection reports in Australian corporations at this stage," said Sinclair.
Allan Bell, marketing director for McAfee Asia-Pacific, agreed: "We have not had any reports of infection from large customers."
Microsoft said it was aware reports of the Zotob worm were circulating. "At this stage, Microsoft has not had any reports of Australian customers who have been affected by this worm. This vulnerability is highly unlikely to result in a widespread Internet attack," a Microsoft Australia spokesperson said.
There are desktop and server versions of Windows 2000, which was released in 2000 for business users rather than consumers. More recent editions of Windows are available, but Windows 2000 remains popular. The operating system ran on 48 percent of business PCs during the first quarter of 2005, according to a recent study by AssetMetrix.
CNET News.com's Michael Kanellos contributed to this report.
