Blizzard says its security team found an unauthorized and illegal access into their internal network here at Blizzard. 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 they currently know, this information alone isn’t enough for anyone to gain access to Battle.net accounts, says Mike Morhalme of Blizzard.
“We quickly took steps to close off this access and began working with law enforcement and security experts to investigate what happened,” he adds. Read more about it at http://us.blizzard.com/en-us/securityupdate.html .