The mailing list for users of the eduroam Configuration Assistant Tool (CAT)

[Brian Epstein <bepstein AT ias.edu>]

Take a look at this article:
https://depthsecurity.com/blog/when-802-1x-peap-eap-ttls-is-worse-than-no-wireless-security
"802.1x supplicants are often configured to trust public CAs from which an 
attacker can obtain a fake certificate."
Further down:
"Install a certificate signed by an internal CA that is trusted by all 
wireless users on the RADIUS server.
Avoid using RADIUS certificates signed by public CAs.
Enforce validation of RADIUS certificates and manually select the internal CA 
to be trusted. Do this centrally, via tools like Active Directory Wireless 
Group Policies if possible. Ensure help-desk personnel and users are not 
capable of modifying this configuration since it has a way of becoming 
disabled when people are troubleshooting wireless issues."
So basically, anyone who can create an InCommon cert could run a fake eduroam 
AP and harvest user passwords. And, they can do it anywhere, like an airport, 
or in a car on your campus.
If you do an internal CA, and force the clients to verify it, your are safe. 
You also avoid having to use an intermediate, and can create a long term cert.
We use Eduroam's Cat tool to deploy, it works well.
All the best,ep
On Feb 14, 2020 03:19, Stefan Winter <stefan.winter AT restena.lu> wrote:


Hello,


> We have a eduroam setup in test mode and am looking at using the CAT
> tool. My question revolves around the intermediate and root certificates.
>
> My understanding is that the radius certs renewal won't affect the end
> users, as long as they are issued by the same intermediate/root certs.
> So I need to make sure the intermediates and roots don't expire any
> time soon, right? If they do, users would have to download a new
> version with the new certificates, right?


That's almost entirely correct.


The root needs to stay the same.


The intermediate can change, but some extra caution has to be applied in
that case: the EAP server needs to send the new intermediate along with
its server cert as a partial chain then, because clients do not possess
the intermediate locally.


It is usually considered good practice to always send the intermediate
anyway, so it's not a big deal. Just something to be and remain aware of.


Greetings,


Stefan Winter


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