Anonymous hits security firm HBGary Federal

In cyberspace they call it “getting pwned”. And that's exactly what happened to American tech security company HBGary Federal when they tried to infiltrate the so-called hacktivist network known as Anonymous.

In an interview over the weekend Aaron Barr, the Washington based company's chief executive, claimed that his firm had successfully infiltrated the shadowy cyber collective behind a series of recent pro-WikiLeaks cyber protests.

Anonymous' revenge was swift and brutal. Using sophisticated hacking techniques, the group managed to deface HBGary's website, break into its messaging system to dump 60,000 emails onto it and hijack Mr Barr's Twitter account to tweet abuse and publish his supposed home address and social security number.

Over the past four years Anonymous have gained a reputation for being one of the internet's most mercurial and chaotic meeting spaces for online mischief makers. But in recent months they have achieved global notoriety thanks to a series of cyber assaults on government and commercial websites that are critical of WikiLeaks.

Their denial of service attacks on companies like PayPal, Mastercard and Visa has resulted in intense police scrutiny with recent arrests in Britain, the Netherlands and the United States as well as increased attempts by private security firms to uncover who, if anyone, is behind the organisation.

Mr Barr claimed his firm had managed to infiltrate Anonymous through their chat rooms and claimed that the organisation was being run by a hardcore of 30 members along with 10 who "are the most senior and co-ordinate and manage most of the decisions." Anonymous have always styled themselves as a somewhat anarchic democratic collective with no leadership.

In a message left on HBGary's website, the successful hackers taunted their would-be pursuers with a statement that read: “You think you've gathered full names and addresses of the 'higher-ups' of Anonymous? You haven't. You think Anonymous has a founder and various co-founders? False."

The attack, which was a significantly more complex hack than recent denial of service assaults used by Anonymous, successfully penetrated HBGary's website through a compromised support server. It mirrors a similar modus operandi used by the group to target ACS:Law, a British legal firm that controversially sent threatening letters to alleged file-sharers. Anonymous responded with frequent cyber assaults, including the leaking of a database of 5,000 alleged porn pirates the firm apparently intended to sue.

Greg Hoglund, the founder of HBGary, has promised his own revenge. "They didn't just pick on any company,” he told cyber security journalist Brian Krebs. “We try to protect the US government from hackers. They couldn't have chosen a worse company to pick on."