[stunnel-users] Three patches

Jason Haar Jason.Haar at trimble.co.nz
Fri Jun 4 02:53:13 CEST 2010

On 06/02/2010 06:28 AM, Tristan Schmelcher wrote:
> If we used verify = 3, we would first of all need the operator to
> download and save those remote certificates to the device. An app
> would help, of course, but simply the existence of this step would
> already present a significant barrier to configuring the device. (For
> example, the operator may not understand why such a step is needed, or
> may not know where to find the application--especially if it has been
> a long time since the ISP purchased the device.) A bigger issue though
> is that the server's certificates could be changed at a later date
> without the operator's knowledge--for example, because they have expired.
Those sounds like design mistakes - not stunnel's to fix. We are also
big users of certs and also have the issue that people involved in
implementation may not (ie don't) understand the whys and hows of PKI. So:

1. make a CA that expires in 2036 (ie infinite future to all intents and
2. make all server certs expire in 2035 (ie they won't expire)
3. ensure your CA pubkey is installed into every app or device that
needs it (Active Directory was great for Windows)
4. ensure everything is set up to support revocation (I just gotta say that)

Doesn't that fix the problem you are trying to solve? The device won't
need to download the certs from the other end, as they are signed by the
CA they already trust. They also effectively never expire - so that
entire issue doesn't need to be managed. We have VPN routers untouched
in nearly 10 years doing this sort of thing. In fact, it's so low
maintenance, people are forgetting how we did it in the first place -
but that's s different problem ;-)

Also your point about "verify = 3" being susceptible to MITM is solved
of course by "verify = 2".


Jason Haar
Information Security Manager, Trimble Navigation Ltd.
Phone: +64 3 9635 377 Fax: +64 3 9635 417
PGP Fingerprint: 7A2E 0407 C9A6 CAF6 2B9F 8422 C063 5EBB FE1D 66D1

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