So let start. My name is Galin Nikolaev Kardjilov. Am I from Bulgaria and I am 15 years old. So I am not sure if this is a bug,but it's very stupid of your side to make it. So when Lilo says Lilo: and you type linux single ,you acceess linux with a bash# and when you type su, you automatically become root. It doesn't promt you for a password. So i can do everything as root. I can change the permissions of /etc/passwd and /etc/shadow to 777 and every user will be able to read/write them. I can change the root password, i can add user and so on. I suggest in the next distribution of RedHat when you go to bash# you go with permissions 500:500 and there must have a speacial command (e.g. svisitor) that prompts you for a special password you have already entered at the installation. So I'd like to receive an email to understand whet have you dicided bye.
This is a long-standing well-known LILO configuration question. Pull up the documentation for lilo.conf and search for the RESTRICTED and PASSWORD options.