Technomyths

A computer virus attacking Microsoft Windows has infected almost nine million machines and is spreading faster than ever before.

Experts say the worm has "skyrocketed" in recent days.

It is sweeping through thousands of offices in the UK and has affected computers at the Ministry of Defence.

The virus - known variously as Conficker, Kido or Downadup - burrows deep into the operating system and tricks the machine into running the infected program.

Once the worm is running on the computer it automatically starts to download more malicious programs from hackers' websites, with devastating effects.

The majority of computers infected by the worm, which was first identified in October, are in Russia, China, Brazil and India. But the virus is now taking hold in the UK.

The worm has password cracking capabilities, often successful because company passwords sometimes match a predefined password list that it carries.

Eddy Willems, a security analyst with anti-virus firm Kaspersky Labs, said that a new strain of the worm was now causing additional problems.

Computer users are advised to ensure their anti-virus software, operating system and firewall is up to date, and that they have installed a Microsoft patch designed to combat the problem.

Experts have also warned the virus could spread by copying itself to USB memory sticks shared between computers, and urged users to use caution.