ZeroAccess, one of the world's largest botnets - a network of computers infected with malware to trigger online fraud - has been disrupted by Microsoft and law enforcement agencies.

ZeroAccess hijacks web search results and redirects users to potentially dangerous sites to steal their details.

It also generates fraudulent ad clicks on infected computers then claims payouts from duped advertisers.

Also called Sirefef botnet, ZeroAccess, has infected two million computers.

The botnet targets search results on Google, Bing and Yahoo search engines and is estimated to cost online advertisers $2.7m (1.7m) per month.

Microsoft said it had been authorised by US regulators to "block incoming and outgoing communications between computers located in the US and the 18 identified Internet Protocol (IP) addresses being used to commit the fraudulent schemes".

In addition, the firm has also taken control of 49 domains associated with ZeroAccess.

David Finn, executive director of Microsoft Digital Crimes Unit, said the disruption "will stop victims' computers from being used for fraud and help us identify the computers that need to be cleaned of the infection".

BBC News