NFS Security Question

From: McGee Olson (molson@crystal.cirrus.com)
Date: 08/13/01 

Message-Id: <200108131706.MAA19040@csparc332.crystal.cirrus.com>
Date: Mon, 13 Aug 2001 12:06:49 -0500 (CDT)
From: McGee Olson <molson@crystal.cirrus.com>
Subject: NFS Security Question
To: focus-sun@securityfocus.com

Hello,

I have been looking for information on securing NFS with respect to root su
abilities. I have read the NFS FAQ at nfs.sourceforge.net and am not entirely
sure of what they said.

Here is an example of what I am trying to figure out:

    1) You have an NIS server providing logins & passwords
    2) You have an NFS server which houses user directories
    3) Each workstation authenticates via NIS
    4) Each workstation mounts the home directories via NFS

So, the scenario goes like this. You have two users "joe" and "bob".
You have two machines "foo" and "bar". "foo" and "bar" both satisfy
(3) and (4) above, and each has a different root password. "joe" has
root on "foo", and "bob" has root on "bar". "joe" logs in as root on
"foo", and then he executes the line "su - bob". Now, "joe" is logged
in as "bob" and has all the permissions associated with the "bob"
account.

Is there anyway to stop this from happening?

Thanks,
McGee 

--
McGee Olson
System Administrator, CAD Systems
Cirrus Logic - Austin

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