Re: [Tsv-art] [tram] Tsvart last call review of draft-ietf-tram-turnbis-25

[Joe Touch <[e-mail]>]

> On Jun 18, 2019, at 6:47 AM, Magnus Westerlund <[e-mail]> wrote:
> 
>> [TR] The comment from Joe is : if TCP-AO is used, application data is authenticated in the TCP leg but the data can be faked when relayed from the server to the peer using UDP. I tried to address this comment by saying if secure application data (SRTP) is used message authentication is available at the application layer even if UDP does not support authentication option.
>> 
> Sure, but this is equivalent to the case of TURN over TCP/TLS that also only have the security model to the middle. So pointing that aspect out is fine, but I think TURN is quite clear on that client to peer security are the responsibility of the end-to-end application using TURN. Like the statement in the Third paragraph of 20.1.4:
> 
>    These attacks are more properly mitigated by application-layer
>    authentication techniques.  In the case of real-time traffic, usage
>    of SRTP [RFC3711] prevents these attacks.

FWIW, even with this statement, if you’re going to talk about preserving IP options and settings then it’s equally important to discuss how you preserve or interfere with TCP options and settings - and maybe other layers like TLS too - in the same place in the document.

It’s not just whether this is a security issue; it’s that the semantics are broken in half.

Joe