Marissa Mayer still can’t explain the massive data breach that affected all users

Former Yahoo CEO Marissa Mayer appeared before the Senate Commerce Committee and admitted that they have not been able to determine who was behind the massive 2013 data breach.

Every single user was affected by the hack in 2013, despite the company only becoming aware of effect of the hack in last December. Yahoo had 3 billion users at the time, making it the largest breach in the history of the internet.


Mayer was initially hesitant to testify at the hearing, saying in June that she was not the best person to ask about certain disclosures that were revealed after that. According to the Wall Street Journal, the committee then authorized a subpoena to force her to testify, she then agreed to appear voluntarily.

The data stolen included names, phone numbers, passwords, email addresses and encrypted or unencrypted security questions and answers. The Department of Justice and the FBI linked the hack to four individuals including two Russian intelligence officers. Marissa Mayer later apologized for the breaches.

“As CEO, these thefts occurred during my tenure and I want to sincerely apologize to each and every one of our users,” Mayer said in opening remarks at the Senate hearing.


Verizon, which acquired Yahoo in June, revealed last month that the breach actually compromised all accounts. Mayer was grilled on why it took so long for Yahoo to disclose the breach and how they underestimated the impact by billions of accounts.

Along with Marissa Mayer, Congress grilled current and former CEOs of Equifax. In September, Equifax revealed that hackers had stolen the personal information of over 140 million US consumers from its website. Mayer left Yahoo in June, walking away with nearly $260 million in stock and severance pay.