Google, Microsoft and Yahoo hit by major hacker attack on internet infrastructure

The attack came on Tuesday and made some websites inaccessible or sluggish.

The company that distributes Google, Microsoft and Yahoo, Akamai Technologies, said there had been a "large-scale, international attack on internet infrastructure". It was not clear who carried out the attack.

All major companies have sophisticated technology to combat hackers, but "cyber-security" is also a big worry for governments fearing terrorist attacks.

By knocking out all or even part of the internet, businesses around the world could be handicapped.

Tuesday’s attack began at 1:45pm BST and lasted for about two hours, according to Akamai Technologies.

Akamai’s network of servers mirrors some of the web’s most popular destinations to improve their performance.

The United States Department of Homeland Security’s cyber-security unit declined to comment. A US government-funded emergency response team said it was too early to determine what happened.

Speedera Networks, an Akamai rival, said it had not been targeted.

Keynote Systems, a web-performance measurement service, said the only sites affected on Tuesday were those served by Akamai.

The company said the availability of the top 40 sites it monitors dropped from 100 per cent to just over 80 per cent during the period in question.

"We discovered it wasn’t the internet as a whole but a few large sites that dropped to nearly zero," said Lloyd Taylor, Keynote’s vice-president for technology and operations.

Other websites affected were those belonging to FedEx, Alta Vista, Lycos and Symantec.

The discovery of a new virus in mobile phones is to be raised in parliament with the Home Secretary, David Blunkett, an MP said yesterday.

Michael Fabricant, the Conservative MP for Lichfield, plans to table Commons questions about the discovery of an infectious worm known as Cabir, which has been found in mobile phones but is not regarded as threatening.