Sony has warned users of its PlayStation Network that their personal information may have been stolen following an attack on their online service.
The company says that data on up to 77 million users may have fallen into the hands of an "unauthorised person."
Nick Caplin, Sony's head of communications for Europe, issued a statement of apology in which he said: "We have discovered that between April 17 and April 19 2011, certain PlayStation Network and Qriocity service user account information was compromised in connection with an illegal and unauthorized intrusion into our network".
The information which Sony believe could have been stolen includes name, address, s-mail address, date of birth, PlayStation Network/Qriocity passwords and login, and handle/PSN online ID.
Caplin added: "For your security, we encourage you to be especially aware of email, telephone, and postal mail scams that ask for personal or sensitive information."
The company has stated that there is currently no evidence that credit card information has been stolen, but advised customers: "If you have provided your credit card data through PlayStation Network or Qriocity, to be on the safe side we are advising you that your credit card number (excluding security code) and expiration date may also have been obtained."
Graham Cluley, Senior Technology Consultant at security firm Sophos commented on the issue saying, "This is a big one." The consultant noted the effects could be greater than expected, with many people using the same passwords for different websites, thus enabling attacks on other services.