[EXT] Freeradius vs Security

Brian Julin BJulin at clarku.edu
Tue Apr 2 16:03:52 CEST 2019

Andre Forigato <andre.forigato at rnp.br> wrote:
> I need to share information about the safety of Eduroam.

Not just eduroam... an advanced attacker can target any SSID.

> If a hacker installs an access point with the name of Eduroam, and this
> access point points to a Freeradius server, it is possible that the malicious
> person sees all the logins and passwords in the Freeradius logs.

Not just FreeRADIUS, though it is probably the tool of choice, attackers
can use any RADIUS server for this.  It does not have to be the same
kind of RADIUS server that the attacked institution uses.

> How to avoid this situation? Should user institutions force their students
> to use personal certificates? (certificate issued by the institution itself to its students)

If you can, the safest way to do it is to provision all clients with
a trusted root certificate for a local CA, and when doing so, lock the clients
to a particular DN, and if possible, to a particular set of CA roots.
How you can configure a client... depends a lot on the client.  Not
all clients are as safe as others.  Old Androids are especially bad.

If you actually can install your own root on your clients, you can
probably also use EAP-TLS without passwords.  Many people prefer
this system to MSCHAP or TTLS.   The drawbacks are that usernames
from the certificates will be easy to sniff out of the air (no privacy protection),
and if a device is stolen, the user is unlikely to know how to revoke the
certificate themselves, versus changing their password, which hopefully
most of your users know how to do.

The second best way to do this is with a public CA.  In this case to be
safe you need your clients to configure to only trust certificates ending
in a domain name for which no responsible CA will issue certificates to
anyone but you.  This puts a lot of trust in the public CA system, and it
is very hard to get users to properly configure their devices.  You also
have to pay attention to when the public CA roots expire and which
clients have which public CA roots in their default operating store.
The advantage to this system is it is possible to set up a client securely
entirely by hand if you know what you are doing... there is no need
to download and install extra configuration profiles (except on OSX and iOS
because they took away the options to secure things by hand a couple
of years ago).  The problem, of course, is that most users do not know
what they are doing and they will just type in their password when asked
and the client will not have the correct settings.

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