Ubuntu Security :: Password Hacking By Bruteforce?

I think it is very easy to hack passwords in Linux, but I did not try it yet. If you use sudo you get 3 attempts for the correct password. But if you get enough time it should be no problem to hack it by bruteforce. Imagine a script an attacker places on your machine which runs for a few hours or days. I think it is much more effective to delete the user out of the admin (or adm?) group so that user cannot be any danger anymore. You would have to login with root and readd the user then.

You now say: but if you login with root you got almost the same effect as with sudo. Of course it is the same. That is why I would use a system (not sure which yet) to create sub enviroments of your OS, which got the attribute that they can run without root, only got one account that can sudo and once sudo access is denied there is no other way to login as root. You just can repermit sudo access by the parent os layer.