In what could be one of the biggest breaches of all time, Yahoo on Thursday confirmed "at least" 500 million user account credentials were stolen in 2014. The possible user information that may have been compromised as part of the hack includes names, email addresses, and hashed passwords.

A note on Yahoo's investors' page says the hack was "state-sponsored," and that the company is working with law enforcement to find out who perpetrated the act.

"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," Yahoo said in a statement on Thursday.

Yahoo is encouraging users to change their password and security questions for accounts that may have been affected. In addition, Yahoo says users should avoiding clicking on links or downloading attachments from suspicious emails.

If you're worried about your account being compromised, you should change your information as soon as possible. You can read Yahoo's full statement at the source link below.