Form vulnerable to SPAM

There appears to be some sort of vulnerability in Register Plus Redux that has opened up our site to spammers. Despite requiring several fields (including First/Last Name and About Yourself), spammers are still able to register for User accounts without entering any of this information. We have the settings configured so the accounts must be moderated, but that doesn’t have any affect on the spam messages that are coming in daily. Any idea how we can protect ourselves from this and/or when this bug will be fixed? Or do we need to find another solution?

http://wordpress.org/plugins/register-plus-redux/