[Ach] OpenVPN and ACH

Reed Loden reed at reedloden.com
Wed Feb 18 20:34:09 CET 2015


Just to follow-up to what Thomas said...

I worry about throwing OpenVPN away so quickly... It's used by *lots* of
people and companies, and it's not going away anytime soon. I agree that
until they have patches like
https://community.openvpn.net/openvpn/ticket/301 landed that it's not going
to be viably secure, but I worry about the complete lack of OpenVPN detail
that people are going to either use the defaults or use random hardening
guides that don't give the entire picture.

I think ACH should continue to mention OpenVPN with warnings about it being
insecure until certain features/patches are added. Basically, provide the
best possible 'secure' config with what it supports today and continue to
evolve that over time as OpenVPN improves. Mention to people the specific
things it lacks in order to be properly secure as per ACH standards so they
know the risks they are taking by using it.

just my 2c,
~reed

On Wed, Feb 18, 2015 at 11:11 AM, Thomas Preissler <thomas at preissler.co.uk>
wrote:

> On Wed, Feb 18, 2015 at 07:48:21PM +0100, Aaron Zauner wrote:
> > Hi,
> >
> > https://github.com/BetterCrypto/Applied-Crypto-Hardening/pull/91
> >
> > I've since removed (commented-out) the OpenVPN section in our document
> > in commit 7b6fd17814acdbb2304ca3e84e99b02fe919abe6.
> >
> > If anybody is interested in maintaining and reviewing this, please speak
> > up. To the best of my knowledge OpenVPN is not suitable for our document
> > -- CBC-only support (not as a fallback) is a real threat to the
> > transport security. Hence I would not recommend using it myself and have
> > thus removed it from our document for the time being.
>
> Considering that more and more people will use this document to
> 'securely' configure their server, but an increasing number of those
> won't necessarily understand the implications why certain services are
> configured that way.
>
> For example, I read somewhere that quite a number of people just use
> certain 'recommendations' somewhere to configure their webserver, then
> go off to SSLlabs and when they get at least an A rating, they are
> happy - admitting they have no clue, what they have just reconfigured.
>
> I believe that this should go in there, as it is not secure. And you
> gave good reasons why it cannot be secure.
> In general, I think it is not a matter of configuring encryption
> securely, it is also about getting the message out that certain services
> are inherently insecure. How else would they stop using it when they
> don't know about it? You could also see this as a wakeup-call for
> developers, maybe to work more closely with cryptographers.
> You also have now a note on SHA-1 in it...
>
> Otherwise people will assume, OpenVPN default's are 'secure',
> configure it themselves with some random tutorial they found somewhere,
> or worse, use some exciting DES encryption - because that's what they
> remember.
>
>
> Kind Regards
>
> Thomas
>
> --
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