SAN FRANCISCO, Dec. 15 (Xinhua) -- Yahoo! Inc. said Tuesday it has identified "data security issues" concerning more than one billion Yahoo user accounts.
The breach, additional to what was revealed in September, that 500 million Yahoo accounts were exposed, was initial found by law enforcement, which provided the company with data files that a third party claimed was Yahoo user data.
Yahoo, based in Sunnyvale, Northern California, analyzed the data with the assistance of outside forensic experts and found that it appears to be Yahoo user data. And further analysis prompted Yahoo to believe that an unauthorized third party stole the data in August 2013.
For affected accounts, it said, the stolen user account information did not include passwords in clear text, payment card data, or bank account information, but may have included names, email addresses, telephone numbers, dates of birth, hashed passwords and, in some cases, encrypted or unencrypted security questions and answers.
The technology company, a pioneer in the early years of the Information Technology (IT) age, acknowledged that it has not been able to identify the intrusion associated with the theft.