Re: [Emu] Idea: New X509 Extension for securing EAP-TLS

[Jan-Frederik Rieckers <[e-mail]>]

On 12.11.19 10:28, Michael Richardson wrote:
> You were trying to do a CSR with some extra attributes with a CA (using
> ACME? Using LetsEncrypt?) and the CA ignored the things that it couldn't
> verify?

No, it was a direct request to the CA of our research network. The
problem here was, that the CA itself would have had to clarify this with
their CA (Telekom Trust Center), because it would mean to set up a new
certificate profile. And that wasn't possible for this one usecase.

> So, as I understand it, the enrollment process for laptops/phones into
> WPA-Enterprise does not include retrieving a set of anchors for that
> connection.  Or that it is just too hard to do.   It works fine if the
> devices are compelled by their corporate masters, but this fails for
> BYOD, and it fails for cross-realm (which eduroam is).

It doesn't. In eduroam this has lead to cat.eduroam.org, where the
installers can be downloaded. As Carsten Borman and I already have
written in a submission for the IAB DEDR workshop[1], with the need of
this tool we also could have used client certificates instead of
username/password combinations.

For a long time it was easy to connect to eduroam without certificate
checking. Especially Android had a very insecure default setting and
most of our users just typed in their username and password and
connected to eduroam without any certificate check. And if the inner
authentication then defaults to PAP an attacker could get many
credentials just by setting up a rogue access point in a crowded place.
And many universities in Germany use PAP because they don't want a
NT-Hashed password in their database.

With the expiry of the old Root CA all clients had to change their
configuration, because (if set up correctly) the root ca was in fact pinned.
We used this rollover to force all our users to use a specific outer
identity, to encourage the use of the CAT.
Since the expiry we also deny all requests with any other outer identity
before the EAP-TLS handshake, to prevent certificate warnings on the
user devices.

Jan-Frederik

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1: https://www.iab.org/wp-content/IAB-uploads/2019/05/p16-bormann-wifi.txt