Restricted Shell for SSH Server

If you use SSH Logins you can lock down the Console to a restriced shell with less enabled commands! This does not work with installed tmux or screen, cause Users can break out of rbash!

• Login as root User on the Server
• install rbash with:

apt-get install rbash

• rename bash by:

mv /bin/bash /bin/oldbash
chmod o= /bin/oldbash

• create a symlink for rbash to bash

$ln -s /bin/bash /bin/rbash

3. enable rbash by system setting /etc/shells

$echo '/bin/rbash' >> /etc/shells

4. set user shell to /bin/rbash

$chsh   #set user shell to /bin/rbash

5. Disable "chsh" command for users

$chmod o= /bin/chsh

6. Login as user and test linux commands.. 7. Purge tmux and screen Multiplexer!