NEW YORK — Yahoo said Wednesday that hackers stole data from more than one billion user accounts.
"Following a recent investigation, we’ve identified data security issues concerning certain Yahoo user accounts. We’ve taken steps to secure those user accounts and we’re working closely with law enforcement," Yahoo Chief Informational Security Officer Bob Lord wrote in a statement.
The hack, which Yahoo says happened in August 2013, is a different breach than the one disclosed in September.
Stolen user account information may contain names; email addresses; telephone numbers; dates of birth and hashed passwords. In some cases the hackers may have gained access to encrypted or unencrypted security questions or answers.
The company does not believe that bank-account and credit card information were obtained by the hackers.
Yahoo is notifying the affected customers and taking steps to secure their accounts.
"We continuously enhance our safeguards and systems that detect and prevent unauthorized access to user accounts," said Lord.
Customers are encouraged to change their passwords and security questions; review accounts for suspicious activity and avoid clicking or downloading attachment from unknown emails.
Lord says they have not been able to identify who is responsible for the breach.
The announcement comes just months after Yahoo confirmed a data breach with at least 500 million user accounts. Yahoo believes a "state-sponsored actor" was behind the hack.
This is a developing story, check back for updated information.