Around half a billion Yahoo accounts were compromised in a security breach in 2014, it has been confirmed.
The hackers, whom Yahoo has said were state-sponsored, accessed names, email addresses, phone numbers, birth dates and even security questions and answers, as were encrypted passwords.
The news could very well cast doubt over Verizon's proposed $4.8bn acquisition of the company which was announced in the summer. Indeed, Verizon told the BBC that it only learned of the hack this week.
A recent investigation by Yahoo has confirmed that a copy of certain user account information was stolen from the company's network in late 2014 by what it believes is a state-sponsored actor,” the official statement said.
Based on the ongoing investigation, Yahoo believes that information associated with at least 500 million user accounts was stolen and the investigation has found no evidence that the state-sponsored actor is currently in Yahoo's network. Yahoo is working closely with law enforcement on this matter.
Online intrusions and thefts by state-sponsored actors have become increasingly common across the technology industry. Yahoo and other companies have launched programs to detect and notify users when a company strongly suspects that a state-sponsored actor has targeted an account. Since the inception of Yahoo's program in December 2015, independent of the recent investigation, approximately 10,000 users have received such a notice.”