Yahoo today admitted that at least 500 million user accounts were compromised by hackers in a late 2014 attack. The hackers were able to grab customer information, including names, email addresses, phone numbers, birthdates, and hashed passwords, as well as both encrypted and unencrypted security questions and answers.
The ongoing investigation suggests that stolen information did not include unprotected passwords, payment card data, or bank account information; payment card data and bank account information are not stored in the system that the investigation has found to be affected. Based on the ongoing investigation, Yahoo believes that information associated with at least 500 million user accounts was stolen and the investigation has found no evidence that the state-sponsored actor is currently in Yahoo’s network. Yahoo is working closely with law enforcement on this matter.
Yahoo will be notifying all affected users, and will ask them to change their passwords immediately, if they haven’t changed them since 2014. All security questions and answers have also been invalidated.
We are taking action to protect our users:
- We are notifying potentially affected users. The content of the email Yahoo is sending to those users will be available at https://yahoo.com/security-notice-content beginning at 11:30 am (PDT).
- We are asking potentially affected users to promptly change their passwords and adopt alternate means of account verification.
- We invalidated unencrypted security questions and answers so they cannot be used to access an account.
- We are recommending that all users who haven’t changed their passwords since 2014 do so.
- We continue to enhance our systems that detect and prevent unauthorized access to user accounts.
- We are working closely with law enforcement on this matter.
We encourage our users to follow these security recommendations:
- Change your password and security questions and answers for any other accounts on which you used the same or similar information used for your Yahoo account.
- Review your accounts for suspicious activity.
- Be cautious of any unsolicited communications that ask for your personal information or refer you to a web page asking for personal information.
- Avoid clicking on links or downloading attachments from suspicious emails.
The company suggests users begin using a Yahoo Account Key to access their account, a simple authentication tool that eliminates the need to use a password altogether. We use this system for our little used Yahoo account, and we highly recommend it. You enter your Yahoo username, and are sent a temporary password via your mobile device.
The online firm began investigating the data breach earlier this summer, after it was discovered that hackers were selling account access online.