Yahoo confirmed Thursday that more than 500 million user accounts user account information was stolen from the company’s network in late 2014 by what it believes is a state-sponsored actor.
The stolen account information may have included names, email addresses, telephone numbers, dates of birth, hashed passwords (the vast majority with bcrypt) and, in some cases, encrypted or unencrypted security questions and answers, the company’s CISO, Bob Lord said in a Tumblr post.
According to Yahoo, it is working with law enforcement and 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.
Contrary to earlier reports, Yahoo said it has found no evidence that any state-sponsored actor is currently in Yahoo’s network, although it did not say if they had accessed the network earlier.
Yahoo has already taken actions to protect its users by notifying those who may potentially have been affected, asking them to change their passwords and adopt alternate means of account verification. The company said it invalidated unencrypted security questions and answers so they cannot be used to access an account, and is also recommending that all users who haven’t changed their passwords since 2014 do so.
Yahoo is asking users to consider using its Yahoo Account Key, a simple authentication tool that eliminates the need to use a password altogether.
Steps to take:
- 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.