Different user I used to login earlier was in root group.
There should ONLY be one ( 1 )
user in that group " ROOT"!
If you NEED to give some outer users SOME!!! root control, that is what "SUDO" is for .
if you are really paranoid
use a OS that uses SELinux
RHEL,CentOS,Fedora ( suse ? it can but a custom build )
be aware if the ownership and se context of "bashrc" & "profile" are wrong or edited so that a NON root user can edit it
SELinux will STOP!!!! the boot with a WARNING!!!!