Server certificate and clients (eap-tls) certificate

[Alan DeKok]

On Dec 11, 2017, at 10:43 PM, Nathan Ward <lists+freeradius at daork.net> wrote:
> 
> I have not tried using a certificate_file that is not trusted by the CA in ca_file, perhaps it doesn’t relate. The documentation seems to indicate that the ca_file is presented along with certificate_file, but, I am not certain, as that is in the radsec stuff not EAP.

  The server certificate has to be signed by a CA in the ca_file.  For EAP-TLS, the entire certificate chain is presented to the other end.

> However:
> - If you use a 3rd party CA for ca_file, they can create fake users (and could be expensive unless you buy a certificate which can sign certificates..)
> - If you use a 3rd party CA signed cert for certificate_file, they can create a certificate that impersonates your RADIUS server, and set up fake APs/whatever. This is the main concern.

  Most modern OSes use "certificate pinning".  Which means that they cache the server certificate on first authentication, and then allow only that certificate.  Which mitigates the concern, but doesn't remove it entirely.

  The recommendations for self-signed CAs still stand.

  Alan DeKok.