[secdir] Secdir last call review of draft-ietf-ippm-twamp-yang-08

[Adam Montville <[e-mail]>]

Reviewer: Adam Montville
Review result: Ready

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.

The summary of the review is: Ready; the Security Considerations cover
in-transit protections well enough, and recommends controlling access to
writable nodes.

One suggestion I have is that the security considerations could do a better job
drawing a straight line between "a number of nodes...which are writeable" and
the "Examples of notes that are particularly vulnerable..." The example is
simply, "...several timeout values put in the protocol to protect against
sessions that are not active but are consuming resources." This would suggest
that controlling access to writable timeout values would mitigate denial of
service, which could be beneficial to state explicitly. Are all of the other
writable nodes of the same character, or would some lead to, for example,
privilege escalation? In other words, while doing so is probably not strictly
necessary for the success of the draft, making the security issues as clear as
possible for at least each category of writable node seems like a good idea to
help those who may not otherwise be aware.