NFS security

[Chuck Karish]

In article <126 at leibniz.UUCP> tpc at leibniz.UUCP (Tom Chmara) writes:
>Not sure this is a question requiring wizardly knowledge, but I have
>been informed that NFS is NOT particularly secure; i.e. "root"
>on one machine can wreak havoc on another (I'm not speaking of
>removing files from a r-w directory etc).  The speaker was not
>overly clear about what the hole was, but he smugly assured me that
>he could do much as he pleased if I were to allow him NFS access from
>a machine on which he was root.  Is this a problem with NFS, or
>with the HP or Apollo versions of NFS?

Some implementations of NFS assume that user ID numbers are congruent
on server and client.  This means that a bad guy can empower a
Trojan horse on the remotely-mounted filesystem, then use it from
the server machine to get privileged access.  This would seem to be
a risk only if the user has login access to both machines.

Do current versions of NFS provide a way for managers to control mapping
of user ID's?  IBM's Distributed Services does, but it's not available
from other vendors.

Chuck Karish	ARPA:	karish at denali.stanford.edu
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