"Separately, we previously disclosed that our outside forensic experts were investigating the creation of forged cookies that could allow an intruder to access users’ accounts without a password. Based on the ongoing investigation, we believe an unauthorized third party accessed our proprietary code to learn how to forge cookies."
While I agree with your sentiment towards security questions, they are irrelevant when something like that is done. A bit scary.
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Anecdotally, I had a time where I couldn't remember may answer to a secret question except that it was a type of food. I called in and the human on the other end let me reset my password with just that explanation. Take that for what you will, but it seems like if someone knows you use passwords that are random strings, they can use that to break in.
"Your mother's maiden name has four numbers in it?"
"It's a password. You should never use real answers for security questions."