Last Call Review of draft-ietf-dna-simple-
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 document provides a simple procedure (for some value of
“simple”) to detect whether an IPv6 node is reconnecting into a
network it’s previously seen.
I should prefix these comments by a big disclaimer re: my very
basic IPv6 expertise.
The Security Considerations are focused on one specific
aspect, namely the use of SEND. I think we should make clear here that none of
the DNA operations by themselves add any measure of security, unless SEND is
actually used. Specifically, I suggest to add the text: “The DNA
procedure does not in itself provide positive, secure authentication of the
router(s) on the network, or authentication of the network itself, as e.g. would
be provided by mutual authentication at the link layer. Therefore when such assurance
is not available, the host MUST NOT make any security-sensitive decisions based
on the DNA procedure. In particular, it MUST NOT decide it has rejoined a network
known to be physically secure, and proceed to abandon cryptographic protection.”
4.1: DUID - is this the host’s DUID or the router's? Per
RFC 3315, both have such a value.
4.3: "all currently configured IP addresses" - but
only for this physical interface, right?
4.8: why is no DAD performed? Someone else might have joined
the network while I was disconnected, and has a duplicate of my address.