Microsoft support customers received a nasty surprise yesterday when it emerged that a number of the software giant's update files had been infected with the FunLove virus.

According to an alert sent out to the company's Premier Support and Gold Certified Partners customers, the infection period spanned "approximately two weeks from Friday 6 April 2001 to Friday 20 April 2001". Microsoft said it is still unaware how the virus got into the network.

Apparently, one server in a chain did not have antivirus software installed, although the software giant has said that all other servers were protected.

The FunLove virus infects .exe, .scr and .ocx files on Windows machines. It then copies itself to other machines on the local network. If it infects an NT 4 machine it will allow all users access at administrator level.

Microsoft said it believes that only around 170 infected update files were downloaded, and that the customers have been notified.

However, concerned users should contact their relevant Microsoft account manager. In the meantime the company has blocked access to a number of update files to that ensure customers are protected.