Hackers have compromised the systems of games developer Valve and stolen customer data from the firm's Steam gaming service.
The company said that the intrusion took place last weekend and resulted in the defacement of Steam's forums and the breach of a database containing user names, email addresses, purchase history and billing addresses.
Valve said that the attackers also obtained credit card numbers and passwords, but that this information was encrypted.
"We do not have evidence that encrypted credit card numbers or personally identifying information was taken by the intruders, or that the protection on credit card numbers or passwords was cracked," Valve said in a statement.
"We don't have evidence of credit card misuse at this time. Nonetheless, you should watch your credit card activity and statements closely."
The Steam forums will remain closed while an investigation continues. Subscibers will be required to change their forum passwords, but the Steam service will not require a password reset.
The breach adds to a long list of hacking incidents this year. Sony made headlines this summer when hackers from the LulzSec campaign attacked databases containing information on the PlayStation Network, which left the service inaccessible for weeks and landed Sony in court.
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