Last Call Review of draft-ietf-mediactrl-architecture-
I have reviewed this document as part of the security directorate's
ongoing effort to review all IETF documents being processed by the IESG.
These comments were written primarily for the benefit of the security
area directors. Document editors and WG chairs should treat these
comments just like any other last call comments.
This is an architecture document describing a framework for media server
control which combines elements from several related working groups and
protocols. The framework described in this document consists of 3
elements: the application server, the media server, and the user agent.
The document focuses on the interactions between the application server
and the media server, and declares the user agent interactions to be out
The security considerations section says that media servers use the
security mechanisms of SIP to authenticate requests from application
servers, and to ensure the integrity of those requests, and says that
this ensures that only authorized application servers may access the
media server and impact its resources.
I have two concerns: first, the current security considerations section
focuses on the media server and how to protect against malicious
application servers (or AS impersonators) -- it should also address the
flip side of this, i.e. what happens if someone impersonates the media
server, and what, if anything, should be done? If this is addressed in
some other related document, then perhaps a pointer to that other
document would be helpful.
My other concern is a bit more nebulous: this work seems to cut across
multiple other efforts (more than I have time to seriously review right
now), and while I think it makes sense to reference the security
considerations of other documents when they adequately address the
problems at hand, I think the wg (and security ADs) will want to be sure
that the particular threats of this framework are explicitly called out
and completely addressed. This architecture document may or may not be
the right place to do that.