FURUNO FELCOM 250 and 500 devices allow unauthenticated access to the xml/permission.xml file containing all of the system's usernames and passwords. This includes the Admin and Service user accounts and their unsalted MD5 hashes, as well as the SMS server password in cleartext.

FURUNO FELCOM 250 and 500 devices allow unauthenticated users to change the password for the Admin, Log and Service accounts, as well as the password for the protected "SMS" panel via /cgi-bin/sm_changepassword.cgi and /cgi-bin/sm_sms_changepasswd.cgi.

FURUNO FELCOM 250 and 500 devices use only client-side JavaScript in login.js for authentication.