Sony has admitted that hackers have accessed the personal details of millions of PlayStation Network users that may include credit card details.
The network's 77 million users have been told by e-mail that they are at risk of fraud and warned to keep a close eye on their bank accounts.
After almost a week of claims by Sony that its PlayStation Network was undergoing maintenance, the company finally admitted that it had been hit by a hacking attack.
The company has now revealed that the hackers stole names, addresses, e-mail addresses, birthdates and PlayStation passwords.
"While there is no evidence credit card data was taken at this time, we cannot rule out the possibility," the company said.
Customers are unhappy that the company did not encrypt the personal information and has taken so long to let them know that the data had been compromised.
Sony is urging users to be on the look out for e-mail, phone and postal scams requesting personal information.
After the data breach at marketing firm Epsilon, some users received e-mails about an application they could download to track whether their information was being misused, but the application recorded everything they typed on their computers, including passwords, according to the Financial Times.
Security experts say PlayStation Network users who used the same passwords for other online services should immediately change those login credentials.
Sony says it is working on increased security for the PlayStation Network, but has given no indication when it will be up and running again.