There are different ways to restrict what a user can do on a system and there are a lot of reasons why we would restrict a user's ability to interact with a system: maybe we want a user just to be able to copy a file to and from the system or to have a simple home where they can work on their tasks without peeking around the system. Anyway, whatever is our goal we can start working with a restrict shell.
Bash itself offers an additional layer of security using the following options:
- rbash
- --restricted
- -r
Invoking rbash or simply bash with the --restricted or -r options spins a Bash instance that trims down what the users will be able to do on such an environment:
- The user cannot change the directory using the cd builtin. The user will be prevented to set or unset the values for the following environment variables:
- BASH_ENV
- ENV
- SHELL
- PATH
- The user...
