If you are root user, try chmod 700 /bin/bash file. It will allow only root user to run the shell files.
This will possibly break some things on your server, since there are usually other legitimate unprivileged system accounts that need to run shell scripts. This will also prevent anyone from logging in as a normal user unless you change that user's default shell.
The more important question is, what scripts are you trying to keep from running, and what users are you trying to prevent from running those scripts?