According to an official statement from the publisher to users, "As a result of our continuing investigation, we have now confirmed that the database in which we store personal information was NOT accessed during the recent server intrusion. Therefore, your personal information was not compromised by an unknown third party.”
Square-Enix had originally feared that up to 1.8 million accounts might have been compromised; said accounts included such information as names, phone numbers, and email addresses, which could be used as phishing tools.
However, the publisher will not be restoring servers until the end of December as a precaution, which had been shut down on the 15th December.