Flaw in su allows root access?

system · 12-18-2001, 09:59 PM

I am aware that RedHat comes set up to only allow root to log in through particular devices (eg. console). Root is not allowed to log in through telnet correct? But, I can log in as a user through telnet then su to become root!! Isn't this a security compromise? I realise it may be dependant upon having telnet open, but jeeze!! That seems like a BIG hole to me! It completely subverts the idea of restricting which devices root can log in on!

system · 12-18-2001, 11:02 PM

Here is some more interesting info on this: while logged in on telnet and using su to gain root acces, whoami returns "root", but users returns the username and not root.

unSpawn · 12-19-2001, 01:20 AM

No it ain't strictly speaking, because su has no relation to telnet security-wise. OTOH if you're using PAM, you could protect from su usage by defining extra necessary authentication, like users to be in the "wheel" group to be able to use su at all.

The overruling and bigger compromise in this case would be effectively *using* telnetd on a box, because now you have transmitted all login name/passwd combo's/any data in cleartext over the 'net.