Four years after the Internet’s biggest data breach ever, Yahoo still has no idea who was behind it, how it was done or even when exactly it happened.
“We have not been able to determine who perpetrated the 2013 breach,” former Yahoo CEO Marissa Mayer said during testimony Wednesday before the Senate Commerce Committee.
All 3 billion of Yahoo’s users as of 2013 were affected by the hack, which the company only became aware of in December 2016. At the time it thought one billion of its accounts and been compromised.
At the time Yahoo had 3 billion users, making the breach far and away the largest in the history of the Internet.
It was only in 2016, when law enforcement brought files to Yahoo containing user information that had been found online, that it even realized its defenses had been breached, she said. Because of the information contained in the field, Mayer said the company was confident that the breach occurred in 2013.