The HG8245 has sever security issues. By default, the admin user telecomadmin is enabled with password admintelecom. It is not possible to disable this user, or change the password. Within the web interface you can change the default password of the default user root, the user name can also not be changed.
To make matters even much worse, access to the web interface is enabled, and there is not option to turn it off. The only way is to set a a port forwarding rule for port 80. Log in to the web interface, go to Forward Rules and then click Port Mapping Configuration on the left. Click New and enter a port forward to either your web server or to a non existent machine for ports 80-81.