Any security issues showing if a certain e-mail address was found in a database or not when a enduser requests a password-reset on a certain homepage or should the homepage just return some kind of generic error or maybe just ignore the error and claim that a mail was sent ?

Thank you

marked as duplicate by Arminius, schroeder Aug 31 '17 at 23:55

This question has been asked before and already has an answer. If those answers do not fully address your question, please ask a new question.

up vote 0 down vote accepted

I would recommend to use a generic message which doesn't disclose the existence or non-existence of addresses.

The main problem would be that an attacker could find out if a specific person is using your website. Depending on the kind of website, that can be a rather important issue (see eg ashley madison). Even for non-sensitive websites the information may be interesting for attackers though (eg to find targets for phishing attacks).

Note though that if you do prevent disclosure when resetting, you should also prevent it when registering. Here, it can actually become a usability issue, so you should weight advantages and disadvantages carefully.

Yes.

This exposes an whether an account exists for that email address. An attacker would know that is a valid account.

This is really a usability versus security question.

Do you want your site to deceive users if an account doesn't exist and not give up information about which emails have accounts? Then claim a mail was sent.

Or do you want to leak whether an account exists or not and give a more meaningful message to users? Then tell users they haven't registered with the service yet.

You need to decide what is more important, the usability or security.

Not the answer you're looking for? Browse other questions tagged or ask your own question.