source: https://www.securityfocus.com/bid/7328/info

Ocean12 Guestbook Manager has been reported prone to sensitive information disclosure vulnerability.

An attacker may make a request for and download the underlying Access database file that is used by the Guestbook Manager. Guestbook administration credentials contained in the database and stored in plaintext format may be revealed to the attacker.

Information collected in this way may be used to aid in further attacks against the system. 

http://www.example.com/guestbook/admin/o12guest.mdb