Re: Is there any encrypted or secure NFS?
On Sat, 3 Jan 2004, Nano Nano wrote:
> On Sat, Jan 03, 2004 at 01:04:21PM -0800, Alvin Oga wrote:
> >
> > > >>>>> "Antonio" == Antonio Rodriguez <arodriguez31@cfl.rr.com> writes:
> > >
> > > Antonio> What would be the best route to establish an encrypted or
> > > Antonio> secure nfs session? I would like to be able to mount a faraway
> > > Antonio> (debian) machine with confidence of not being observed. Any
> > > Antonio> ideas? Thanks.
> >
> > use secure rpc
> > use secure portmap
> > use secure nfs
> > use scp/ssh --> use a good hard to guess/type passphrase
>
> Isn't it possible to mount drives with ssh, so it does the scp
> tranparently?
regardless of method .... the basic underlying nfs structure is insecure
so you're supposed to replace the insecure portmap, rpc services with
something more secure
http://www.linux-sec.net/FileSystem/#NFS
- crackers can get into your box via nfs vulnerabilities
because you have it "on" ( big problem )
or start on another path of coda, intermezzo, afs, ...
( more fun and tricks )
- or even better, use an encrypted fs.. than its no longer an
issue
regardless of method, turn off nfs when not in use and dont use
nfs if at possible
- automounter can umount it for you when its not in use
dumb way ... ( brute force )
user# scp /net/remote-host/mnt/secret/secret-files.txt .
( trivial way and works easily/fast w/ autofs )
remote host should be setup to export /mnt/secret to "user" only
better way ...
better way# ssh -l user remote-host -- and enter your pwd
-- do your magic
-- your reequest for nfs is hereby denied !!
/home is probably the only that should be NFS mounted via an
automounter individually for each users home dir ...
----------------------
if you mean: ( hardway .. worst way )
localpc# ssh remote " mount /dev/hdc /mnt/secret ; \
scp /mnt/secret/salaries.txt . ; umount /mnt/secret "
too messy ... too many assumptions ... no verification/checking
- you dont know that you mounted/umounted properly
- root should never be able too ssh into another pc
- users should never be able to mount remote filesystems
- too many security violations
-----------
remote machine -- should automount /mnt/secret whenever certain users
tries to access /mnt/secret/secret
- if security is an issue, it should never be mounted
except for local users ... and NOT exported
----------
- turn off nfs when not in use
( if you use s script.... mount it before you use the remote fs )
- if security is an issue... that script should be shot
-- if you use scp ... don't use pass phrase like "pass phrase 123"
and dont use user passwd like "spot123" where spot is your dog's name
== all that easily guessable stuff makes ssh useless
== anytime the other machine acccepts root logins w/o passwords
because it uses keys, than the cracker has access to both machines
without knowing any passwds
- problem is people cant seem to live w/o nfs... or dont want to do things
a better way
c ya
alvin
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