Sending the account number out in a URL over SSL should not be that big of a hole
Exposing an internal ID in such fashion is not only foolish, but very much a beginner error. I would expect this from some half-assed forum software - not a bank. That said, I've worked for the government before, and seen the same stupid mistake repeated time and time again. A salted hash would have been a lot less idiotic. The fact that there was no authorization performed makes compounds the issue, however, and one wonder who these people hired to write their infrastructure.
"Lead us in a few words of silent prayer." -- Bill Peterson, former Houston Oiler football coach