Blizzard has announced that their internal network has been compromised and some credentials had been accessed. Upon noticing the breach, the security teams closed access to the network and are working with law enforcement and security experts to investigate further.
At this time, we’ve found no evidence that financial information such as credit cards, billing addresses, or real names were compromised. Our investigation is ongoing, but so far nothing suggests that these pieces of information have been accessed.
Some data was illegally accessed, including a list of email addresses for global Battle.net users, outside of China. For players on North American servers (which generally includes players from North America, Latin America, Australia, New Zealand, and Southeast Asia) the answer to the personal security question, and information relating to Mobile and Dial-In Authenticators were also accessed. Based on what we currently know, this information alone is NOT enough for anyone to gain access to Battle.net accounts.
We also know that cryptographically scrambled versions of Battle.net passwords (not actual passwords) for players on North American servers were taken. We use Secure Remote Password protocol (SRP) to protect these passwords, which is designed to make it extremely difficult to extract the actual password, and also means that each password would have to be deciphered individually. As a precaution, however, we recommend that players on North American servers change their password. Please click this link to change your password. Moreover, if you have used the same or similar passwords for other purposes, you may want to consider changing those passwords as well.
To update your details for Blizzard titles and provide new login information, head over to Battle.net.