A new report from Microsoft itself suggests that no less than 8 million PCs were infected by the "MSBlast" worm since last August. This is an impressive number that far outpaces previous estimates on how broad was the infection around the globe.

The latest data comes from the software giant's ability to track the usage of an online tool that its engineers created to clean systems infected with the worm. Since the January release of the tool, more than 16 million of the systems that connected to Microsoft's Windows Update service were found to be infected with MSBlast and were offered a patch and the use of the disinfecting tool, the software giant told CNET News.com. During the same period, about 8 million systems actually called on Update to patch them and prevent reinfection and used the special tool to remove the worm.