LDAP bind as a user without password?

Question

We have a forgot password system that allows a user to create a new password. It is going against Active Directory over LDAPS. Right now once a user goes to create a new password, we have to bind as an admin, change the password to a random string, then bind to the user account with that random string, then change the password to the one they provided. We do this because we have a password history policy of the last 5 used passwords.

This works fine now but the password history has the random strings as one of the previous passwords. Is there any way to bind with a user but without a password? The user would be authenticated before this by a security question.

Answer 1

I do it a different way. I create a dynamic object under the user's entry, expiring in a few days, with a generated uid attribute; send them a link containing that uid; that leads to the change password page, but logged in via a different LoginModule that sees the UID parameter, checks it, and if present and correct logs them in. In other words a kind of 'ticket' login.

The code that did the lookup bound/reconnected itself as the application itself, but that didn't actually matter because the connection for logging in is closed immediately, like all other LDAP connections in the application actually. When anything is done to the user's own entry, eg change password, update profile, a reconnect is done as that user using the password which I have saved in the session. When the user does anything else to LDAP it is really the application doing it so an application bind/reconnect is done as above. IOW the application itself is a user (or even several different users with different levels of permission).

Because a UID is much longer than a password, and because the entry containing it expires after a day or two, all this is rather more secure than generating a temporary password and shipping it around. The change password page could also have a security question on it if reached via the ticket login.

Answer 2

There are two password change operations in AD - reset and change. Reset is an administrative operation (which is what you are doing here). When you do a reset, you don't need to supply the current password. Change password is an end user operation whereby the user has to supply their current password in addition to the new password.

If you change your code to do a password reset and run in the context of a user with permissions to reset passwords, you should be good to go. If you need to honor password policy during the reset, there's a way to do this as well with a special LDAP control.