Bugtraq mailing list archives

Re: allowing root logins via the network, was Fix for Linux/AIX login hole


From: proff () suburbia apana org au (Julian Assange)
Date: Wed, 25 May 1994 18:26:29 +1000 (EST)


It depends on where you want to draw the line between security and flexibility
(ie. do you want to be able to login as root from home and fix things up or
are you willing to have to come in an be physically at the console for those
- very rare - times when something has gone very wrong).  Sure, I can think
of a number of scenarios when it is nice to be able to login as root via a
telnet session - but they are all times when there is a problem.  We made the
decision a long time ago that we would bite the bullet in such situations and
give up the ease of logging in as root via a telnet session for the security
of only allowing root logins on the console - in our case the extra security
warrants it we feel.  On certain machines (ie. a kerberos or other
authentication key server) I'd even recommend disabling the regular vendor
telnetd, rlogind, rshd, rexecd, rexd, etc.  daemons in /etc/inetd.conf so that
your trusted security server machine doesn't become the first victim!

If being able to get to the console and login as root at remote locations 
(ie., you have isolated Unix boxes running a turnkey vertical application
out at branch offices or franchises where there are no sys admin staff)
is a real necessity I wouldn't recommend doing it via a public TCP/IP network -
I'd put the console (or auxiliary remote console) on a modem with several
levels of challenge on it - perhaps even a callback unit).

As for the issue of allow root rlogin-without-a-password access via the /.rhosts
file so that your root passwords are not captured - there are two ways to
fix this problem.  The first - as you say - is to use Kerberos or a similar
authentication system.  The second is to build a more secure physical local
area network and enterprise (as much of it as you administer) network.  This
can be done by getting rid of the shared LANs (primarily coax ethernet but
also a few other technologies/topologies) as much as possible and replaced
them with hubs providing private, bridged, switched connections (one machine
per port).  Expensive but getting cheaper every day.  These two steps
(and I would also recommend a firewall for most organizations connected to
the Internet) can make a network much more secure.

Or you could just use encrypted telnet or my challenge responce system "Chalace".

- Proff



Current thread: