Yahoo Hack Of 2013 Affected All 3 Billion Accounts, Company Now Says

Yahoo now says that all user accounts were compromised in the 2013 hack that the company notified users about in December. Yahoo had previously said that around 1 billion accounts were affected in the hack but the new disclosure brings that number to 3 billion.

"Based on an analysis of the information with the assistance of outside forensic experts, Yahoo has determined that all accounts that existed at the time of the August 2013 theft were likely affected," the Sunnyvale, California-headquartered company said in an account security update FAQ.

Yahoo noted that when it previously announced the hack, it took action to protect all accounts. It required users who had not changed their passwords since the theft and invalidated unencrypted security questions and answers.

The stolen user information may have included names, email addresses, telephone numbers, dates of birth, hashed passwords (using MD5) and, in some cases, encrypted or unencrypted security questions and answers. Passwords in clear text, payment card data, or bank account information was not stolen.

Yahoo was acquired by Verizon last year and following the purchase it will be merged with AOL to form a new brand known as Oath. (Verizon purchased AOL in the summer of 2015; AOL has an ownership stake in Patch.)

Click here for more information on the hack and what you can do to protect your account.

Patch will update this report.

Photo by Justin Sullivan/Getty Images News/Getty Images