Microsoft yesterday confirmed some of its MSN Hotmail servers were infected with a "Code Red" virus, the computer virus that exploits a vulnerability in Microsoft's server systems.
The news follows Microsoft's extensive public education campaign aimed at getting users to download a simple patch that protects servers from the virus.
It is not clear whether the infections found this week were caused by the first "Code Red" virus or a second, more virulent, virus dubbed "Code Red II".
Both viruses exploit a vulnerability in the company's Windows 2000 and Windows NT server software that was discovered earlier this year. Similar attacks have caused massive Internet slowdowns over the past two weeks.
MSN Hotmail is a free Internet service that has about 110 million registered users, according to Microsoft.
Microsoft spokesman Mr Jim Desler said no customer data, customer e-mails or personal information seemed to have been compromised in the attack.
AP