Verizon finished its acquisition of Yahoo in June and is folding it, with AOL, under a new subsidiary named Oath.
Sorry Boss, I know this is political, but that's a load of hooey.
The company required all users who had not changed their passwords since the time of the theft to do so.
Yahoo also invalidated unencrypted security questions and answers so they cannot be used to access an account," Yahoo said Tuesday.
Yahoo said it will begin alerting accounts that weren't previously notified of the attack.
"As we have previously disclosed, our outside forensic experts have been investigating the creation of forged cookies that could have enabled an intruder to access our users' accounts without a password," a Yahoo spokesperson said in an emailed statement.
"The investigation has identified user accounts for which we believe forged cookies were taken or used.