Re: [secdir] review of draft-hollenbeck-rfc4933bis-02

[Nicolas Williams <[e-mail]>]

On Thu, Jul 16, 2009 at 10:54:24AM -0400, Polk, William T. wrote:
> > Nico's response confirmed what I was thinking about this myself: for EPP
> > running over TLS over TCP (4934bis), channel bindings are not required,
> > because TLS authentication is mandatory and because TLS server
> > certificate verification procedure is also mandatory.
> > So I don't think there is an issue with 4934bis document.
> 
> I'm not so sure... TLS server certificate verification protects the client
> against a MITM attack.  The server has no way of knowing whether this
> procedure has been implemented.  So, the server does not have all the
> protection it needs unless the TLS connection uses client certificate
> authentication as well.
> 
> Channel bindings would extend the level of assurance for the server.
> Alternatively, mutual authentication using certificates would resolve the
> problem as well.

The client can always just post the username & password in a very public
place, spam people with it, ...

Channel binding doesn't protect against that!  ;)