Three billion of Yahoo’s accounts were hacked in 2013

Yahoo has revealed that every single account on its system at the time of the 2013 data breach was affected in the cyber attack previously disclosed by the company on December 14, 2016.

At that time, Yahoo disclosed that more than one billion of the approximately three billion accounts existing in 2013 had likely been affected. In 2016, Yahoo took action to protect all accounts, including directly notifying impacted users identified at the time, requiring password changes and invalidating unencrypted security questions and answers so that they could not be used to access an account. Yahoo also notified users via a notice on its website.

Subsequent to Yahoo’s acquisition by Verizon, and during integration, the company recently obtained new intelligence and now believes, following an investigation with the assistance of outside forensic experts, that all Yahoo user accounts were affected by the August 2013 theft.

While this is not a new security issue, Yahoo is sending email notifications to the additional affected user accounts. The investigation indicates that the user account information that was stolen did not include passwords in clear text, payment card data, or bank account information. The company is continuing to work closely with law enforcement.

“Verizon is committed to the highest standards of accountability and transparency, and we proactively work to ensure the safety and security of our users and networks in an evolving landscape of online threats. Our investment in Yahoo is allowing that team to continue to take significant steps to enhance their security, as well as benefit from Verizon’s experience and resources.”

Chandra McMahon, Chief Information Security Officer, Verizon

“Verizon is committed to the highest standards of accountability and transparency, and we proactively work to ensure the safety and security of our users and networks in an evolving landscape of online threats,” said Chandra McMahon, Chief Information Security Officer, Verizon through a statement. “Our investment in Yahoo is allowing that team to continue to take significant steps to enhance their security, as well as benefit from Verizon’s experience and resources.”

In June 2013, Verizon Communications completed its acquisition of the operating business of Yahoo! at US$ 4.8 billion. The company later combined these assets with its existing AOL business to create a new subsidiary, Oath, a diverse house of more than 50 media and technology brands that engages more than a billion people around the world.

The Oath portfolio includes HuffPost, Yahoo Sports, AOL.com, MAKERS, Tumblr, BUILD Studios, Yahoo Finance, Yahoo Mail and more, with a mission to build brands people love.