500 million Yahoo accounts were compromised in a massive data breach dating back to 2014 by what was believed to be a “state sponsored” hacking group. Yahoo is investigating the breach with law enforcement agency and currently believes that users’ names, email addresses, dates of birth, phone numbers, passwords, and in some cases, encrypted and unencrypted security questions-answers were stolen from millions of Yahoo users. The company does not believe the stolen information includes credit card information or any bank details of the affected users.
Source: https://thehackernews.com/2016/09/yahoo-data-breach.html