Sony has also suggested that the collective known as Anonymous was behind the attacks, since forensic investigators discovered a file on Sony's servers, named "anonymous," that included a fragment of the collective's slogan.
But the collective disavowed all knowledge of the breach, saying in a statement that stealing credit card data isn't its style. "Whoever broke into Sony's servers to steal the credit card info and left a document blaming Anonymous clearly wanted Anonymous to be blamed for the most significant digital theft in history," said a statement from the collective. "No one who is actually associated with our movement would do something that would prompt a massive law enforcement response." Instead, the group suggested that online thieves had left the file as subterfuge.
One positive piece of information revealed by Sony is that, so far, none of the compromised credit card data has been used by attackers. Furthermore, the scale of credit card loss, while large, isn't as bad as first expected. According to Hirai's letter, "globally, approximately 12.3 million account holders had credit card information on file on the PlayStation Network system. In the United States, approximately 5.6 million account holders had credit card information on file on the system. These numbers include active and expired credit cards."
But Sony declined to fully reveal detail how the breach occurred. "We are reluctant to make full details publicly available because the information is the subject of an ongoing criminal investigation and also the information could be used to exploit vulnerabilities in systems other than Sony's that have similar architecture to the PlayStation Network," said Hirai.
In response to legislators' question about whether Sony would be offering credit monitoring services for customers whose information was stolen, Hirai said that instead, Sony will instead offer a "welcome back" package with 30 days of free service.
But will customers return?