Microsoft has resisted a distributed denial of service attack launched against its website by the MyDoom.B worm.

The attack was due to hit www.microsoft.com at 13:00GMT on Tuesday but has so far failed to make an impact.

"I'm not surprised the attack has failed," said David Emm, marketing manager for McAfee Security.

"We've seen very few MyDoom.B infections. Nothing like the numbers of the original MyDoom.A. It's minuscule by comparison."

In preparation Microsoft has set up an alternative address at https://information.microsoft.com.

The A and B variants of the MyDoom worms have also launched a similar attack against the SCO Group's website, www.sco.com. The company is now using www.thescogroup.com as an alternative URL.