Do you get the following message when you sign in your yahoo account ?
Critical – Please provide the following information
You will not be able to sign in to Yahoo! services unless you provide the requested information on this form. This information will help you reset your password in case you ever forget it.
Yahoo! is changing the way you can recover your account in case you forget your password. We recommend that you provide a mobile phone number and/or an email address, but you must enter two secret questions and answers in order to continue.
Enter an email address (Optional): where Yahoo! will send password reset and account emails
Enter a mobile number (Optional): where Yahoo! will send password reset and account alerts
Add two secret questions (Required):
If you provide alternative email address or mobile number and two secret questions and answers, you can recover your account in case you forget your password. This is not a phishing scam. This will also help you to reset your password.