Mydoom virus will target millions

MILLIONS of computer users in Britain were today being warned to prepare for an attack by the fastest growing virus ever to emerge.

The Mydoom worm, which is already responsible for one in four emails sent over the internet, is expected to attack the Microsoft website in an attempt to cripple it.

This would stop more than seven million Microsoft customers sending or receiving emails by hotmail and also prevent them gaining access to the internet.

One US software company, SCO, had its website paralysed yesterday after a large-scale 'denial of service attack' which could continue for another 10 days.

These attacks work by spreading a virus, or worm, to thousands of individual computers which are then programmed to bombard a specific website with requests for information all at the same time.

Both Microsoft and SCO have offered a $250,000 (£137,000) reward for information leading to the arrest and conviction of the creators of the Mydoom worm, which has generated an avalanche of infected emails and

clogged corporate networks since it first appeared early last week.

The first version of the worm, Mydoom.A, also known as Novarg or Shimgapi, emerged last week in the form of a spam email that contained a well-disguised virus attachment.

Analysts now say that hundreds of thousands of computers could have been infected. And while businesses have been quick to protect their systems, home computer users have been slow to respond.

Now a second strain of the virus, Mydoom.B, is expected to assault Microsoft. It was the release of the B virus that last week triggered a warning from the US Department of Homeland Security's alert system.

Experts say that between them the A and B strains have accounted for 30% of all email traffic at their peak - beating all previous records for virus infections.

Because of the number of people using Microsoft, the virus's effects will be felt most among its subscribers. But it can affect all email users.

When a message containing the worm is opened on any email account - for example AOL or BT Internet - the virus sends copies of itself to every entry in the user's address book.

The sheer number of emails will then clog up the internet, making it slower at best and, at worst, impossible to use.

Microsoft's senior vice-president, Brad Smith, said today: 'This worm is a criminal attack. Its intent is to disrupt computer users, but also to keep them from getting to antivirus locations and other sites that could help them. Microsoft wants to help the authorities catch this criminal.'

SCO's worldwide director of IT infrastructure, Jeff Carlon, said: 'We have a series of contingency plans to deal with this problem and we expect to announce them today.'

How to deal with the bug

What will Mydoom do to my computer?

The virus will open your Notepad software, and print random characters. It will then send a copy of itself to all your email contacts. Then it will install an electronic back door so hackers can control your machine. Machines around the world are being hijacked.

How do I get rid of it?

To remove the virus, install the latest anti-virus software definitions. Visit your software vendor's web site.

How many people have the virus?

Several million, it is believed. The virus currently infects one in four emails.

Who created it, and why?

Nobody knows who wrote Mydoom, although a bounty is being offered for information about the author. Experts believe it could be disgruntled computer users unhappy with Microsoft and SCO.