Providing details on a large hacking case, Yahoo says it believes "information associated with at least 500 million user accounts was stolen." The company says its investigation suggests the stolen data doesn't include payment and bank account information, which it says are stored in a different system.
Yahoo suspects that a "state-sponsored actor" performed the hack, stealing users' account information from the company network late in 2014.
That account information could include users' names, emails, phone numbers, and dates of birth, Yahoo says. In some cases, log-in security questions and answers were also stolen. The company has published an FAQ page about the security problems.
An investigation into the hack is ongoing, Yahoo says in a message about the hack, adding that it's notifying users who may have been affected and is taking steps to secure those accounts. The company says it's using email to notify those who were potentially affected; it's also urging users to change their passwords.
Confirmation of the hack comes nearly two months after Verizon announced plans to buy Yahoo for some $4.8 billion in cash.
Today, Verizon says:
"Within the last two days, we were notified of Yahoo's security incident. We understand that Yahoo is conducting an active investigation of this matter, but we otherwise have limited information and understanding of the impact. We will evaluate as the investigation continues through the lens of overall Verizon interests, including consumers, customers, shareholders and related communities. Until then, we are not in position to further comment."