User interface, security, and "simplicity"

[Thor Lancelot Simon]

On Sat, May 03, 2008 at 07:50:01PM -0400, Perry E. Metzger wrote:
> 
> "Steven M. Bellovin" <smb at cs.columbia.edu> writes:
> > There's a technical/philosophical issue lurking here.  We tried to
> > solve it in IPsec; not only do I think we didn't succeed, I'm not at
> > all clear we could or should have succeeded.
> >
> > IPsec operates at layer 3, where there are (generally) no user
> > contexts.  This makes it difficult to bind IPsec credentials to a user,
> > which means that it inherently can't be as simple to configure as ssh.
> 
> I disagree. Fundamentally, OpenVPN isn't doing anything IPSEC couldn't
> do, and yet is is fairly easy to configure.

And yet there's no underlying technical reason why it is any easier to
configure than IPsec is; it is all a matter of the configuration interface
provided by your chosen SSL VPN (in this case, OpenVPN) or IPsec
implementation.

I find it amusing (but somewhat sad) that in fact one can find basically
the same set of flaws in each, but they're considered damning in IPsec
while they're handwaved away or overlooked in SSL VPNs.  Of course you
(Perry) or I can configure either IPsec or OpenVPN in a safe and sane way;
and, of course, there are some VPN packages of either type (IPsec or SSL
VPN) which have configuration interfaces so bad that we _couldn't_, in
fact, set them up safely -- because they prevent safe, sane configuration.

The problem is that whether you or I _can_ set software X up safely isn't
the question that matters.  The question that matters is "_will_ a naive
user who does not understand the underlying security questions set software
X up securely".

And, in fact, most VPN software of any type fails this test.  My concern
is that an excessive focus on "how hard is it to set this thing up?" can
seriously obscure the important second half of the question "and if you
set it up in the easiest possible way, is it safe?"

Thor

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