Mike Morhaime of Blizzard Entertainment has released an announcement that there has been unauthorized access to Blizzard’s internal network.
Morhaime states that they have taken steps to close the breach in security and are now working closely with law enforcement to investigate the situation.
It is important to note that Blizzard does NOT believe that any personal information such as credit cards,billing addresses or real names have been compromised. Although they do mention that some internal data was illegally accessed, including a list of email addresses for battle.net users. Information about players on North American servers such as personal security question, Mobile and Dial-In Authentication we also accessed. However, this information alone is not enough to gain access to battle.net accounts.
Passwords to battle.net accounts were also compromised but these passwords are scrambled using Secure Remote Password Protocol (SRP) which protects passwords.
Blizzard cautions that even though the passwords are scrambled you should still consider changing your password.
An automated process will be coming along in the next few days to get battle.net users to change their secret questions and answers.
For more information on this subject please head to the official link below.
http://us.battle.net/support/en/article/important-security-update-faq