Sony points finger at Anonymous over Playstation data theft

Online group Anonymous has hit back after Sony told the US Congress that the ‘hacktivist' group indirectly allowed hackers to steal personal information from the Playstation Network (PSN).

In a letter to Congress, Sony chairman Kazuro Hirai said the theft of personal data from the PSN occurred while the company was trying to defend itself against a cyber-attack from members of Anonymous.

Sony said forensic expects had discovered that intruders planted a file on one of its servers; the file was named "Anonymous" and contained a phrase that is used by the online group: "We are Legion".

The Japanese technology company claimed it was being subjected to denial of service attacks from Anonymous because it had taken action against a hacker at a federal court in San Francisco.

The denial of service attack, Sony claimed, distracted it from detecting another intrusion that lead to the theft of the personal data of around 100 million users.

The Anonymous group, which came to prominence in December after its members attacked companies that had cut off services to whistle-blowing website Wikileaks, released a statement denying any involvement in the attacks.

In their statement, the Anonymous group said they had "never been known to have engaged in credit card theft" and that they are "trying to fight criminal activities by corporations and governments, not steal credit cards."

Sony's letter to Congress did not suggest that the Anonymous attack and the data-theft attack were directly linked, but it did say: "Whether those who participated in the denial of services attacks [Anonymous] were conspirators or whether they were simply duped into providing cover for a very clever thief, we may never know."

The letter to the US Congress comes after the House's Subcommittee on Commerce, Manufacturing and Trade – a branch of the the House Energy and Commerce Committee – started an inquiry into the breach of Sony's servers.

Congressman Ed Markey, a senior member of the House Energy and Commerce Committee, said: "As millions of Americans increasingly take advantage of the online functionality of videogames, it is critical that Sony protect the private, sensitive information of its users.

"Sony needs to explain how these breaches have occurred, why user information does not appear to have been encrypted and what the company is doing to fix the problem and help consumers whose data was exposed."

The Sony PlayStation Network has been down since Wednesday 20 April. Sony is continuing to investigate the attack.