A colleague and I did something similar recently. We got similar spam mails in our work inboxes. Whipped up a little ruby script that spammed bum login data to the spammer's form url. We had our scripts running on a couple of Heroku instances and all. At some stage we realized that the password field in the form accepted arbitrarily sized payloads. So we base64 encoded some 10MB file and sent that as the password. Th…
It would be quite interesting to do a study on both options using a honeypot-account (to detect whether the login could be extracted by the spammer).