Cybersecurity

I have installed ubuntu. And I have create users ans groups.
Suppose if the user enter into through Putty SSH. He should have access only to home folder and cannot move to other than $HOME. User should not able to root files and /$ files.

Kindly provide solution.

Regards
Vasanth kumar

They have access to whatever POSIX is set to. By default a non admin user will only have rwx access to their own home directory and read and execute access in other places. It depends on how you set up users and groups. If the user is an admin, then they can access anything via sudo.

I am the root user.. I have created users and groups...

Suppose if the non-user enter into through Putty SSH. He should have access only to home folder and cannot move to other than $HOME. User should not able to root files and /$ files.

This totally depends on your set up. Out of the box Ubuntu install is probably only going to all full access to ~/ (home) but not to anything else. However, if the ssh into a linux box they will still get read and execute access to a lot of other files. What exactly are you talking about specifically?

If you set up your own users and groups then it will abide by those POSIX, and if you go even further like ACLs you can add even more settings to it.

When I ssh into my web server I have only rwx access to my ~/ but I have read and execute access to other files. I can use ls and see what is in /etc and I can read some files but cannot write to them, so access is a very broad term. Also you don't need to be the root user to access files/folders owned by root. All you need is sudo access and to be in the /etc/sudoers, and Ubuntu uses this. So any user that is in that group or has that access can gain root privileges via sudo.