Yahoo today disclosed that up to one billion user accounts were accessed by a third party in August 2013.
The outside party was able to steal names, email addresses, phone numbers, dates of birth, hashed passwords, and some security questions/answers. Yahoo says its investigation so far shows that the hackers did not gain access to clear-text passwords, credit card data, or bank account information.
Yahoo has begun notifying those users it believes may be affected and is requiring them to change or update their passwords. Yahoo has also invalidated unencrypted security questions and answers so they may not be used.
The company is encouraging all users to review their online accounts for suspicious activity and to change passwords and security questions. Yahoo recommends people use Yahoo Account Key, which negates the need for passwords. Yahoo has not yet been able to determine who or what entity stole the information.
This incident is separate from the hack that Yahoo disclosed in September.
