Blizzard announced that their servers had been attacked and there was a security breach, which threatens the safety of Battle.net’s accounts. According to Blizzard, no credit card or financial information has been leaked, however, almost everything related to account log-in may have been.
“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.”
“Based on what we currently know, this information alone is NOT enough for anyone to gain access to Battle.net accounts.”
“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.”