BBC News reports:
Online activist group Anonymous has targeted an American security firm that claimed to know the identities of its leaders.
The secretive organisation is being investigated in several countries over strikes on Visa, PayPal and others.
Over the weekend Aaron Barr, head of HBGary Federal, said he had discovered the names of its most senior figures.
The group retaliated overnight by breaking into the company’s website and hijacking his Twitter account.
Anonymous, known for being a loosely-knit group, has been involved in a number of high profile online protests and attacks in recent months.
In December, the group launched a campaign in support of Wikileaks that disrupted services at MasterCard, Visa and other companies that had withdrawn support the whistle-blowing website.
The strike led to police investigations around the world, and a number of arrests in Britain and the Netherlands.
Although the individuals who make up the collective claim they do not have a traditional hierarchy, Mr Barr told the Financial Times that he had infiltrated the organisation and uncovered the names and addresses of several senior figures…