...as they revealed they are victims of the largest cyber breach in internet history, but have kept it quiet for 2 years!
Yahoos announcement:
We have confirmed, based on a recent investigation, that a copy of certain user account information was stolen from our network in late 2014 by what we believe is a state-sponsored actor. The account information may have included names, email addresses, telephone numbers, dates of birth, hashed passwords (the vast majority with bcrypt) and, in some cases, encrypted or unencrypted security questions and answers. The ongoing investigation suggests that stolen information did not include unprotected passwords, payment card data, or bank account information; payment card data and bank account information are not stored in the system that the investigation has found to be affected.
Account Security Issue - Yahoo
It's incredible, how could this go unnoticed for 2 years?
Then the cynical side of me noticed the story on the beeb about Verizon buying Yahoo in July for £3.7bn. Now a deal that size would have taken a long time to negotiate and finalise. Maybe, a year, 18 month. Maybe a month or two after some techie realised what had happened? 
Obviously just my unfounded cynical speculation...
Verizon told the BBC it had learned of the hack "within the last two days" and said it had "limited information".
It added: "Until then, we are not in position to further comment."
BBC News - Yahoo 'state' hackers stole data from 500 million users
