Thus far the largest hack has been attributed to MySpace, which affected around 427 million accounts. Yesterday as the numbers were still unclear suggestions of 200 million or hundreds of millions were circulating.
According to Yahoo among the leaked information are:
- Names
- Email addresses
- Telephone numbers
- Dates of birth
- Hashed passwords (the vast majority with bcrypt)
- In some cases encrypted or unencrypted security questions and answers
As always with these hacks, you should change your Yahoo password if it has been the same since late 2014. Also change the password on other services that have the same password.
Yahoo has said that it's working with law enforcement to get to the bottom of the hack and will inform the affected users.