Subject: [secdir] Secdir review of draft-ietf-dhc-dhcpv6-vendor-message-01

From: Tobias Gondrom <[email-masked]>
Date: Mon, 15 Feb 2010 16:24:24 +0000

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 draft correctly states that the introduction basically allows each
vendor to introduce its own security problems based on the functionality
triggered by the vendor specific messages. The specification that "Relay
agents SHOULD relay these messages ...  unless the relay agent
understands the specific message and knows that the message was directed
at it." can worsen security risks by allowing quite far reaching/remote
attacks as relays will forward any vendor message which they do not
understand. Although this paradigm makes sense for network operation,
this may result in unintended side effects regarding security and attack
vectors.

1. COMMENT on section 3 on page 3:
-  msg-type             VENDOR-SPECIFIC (TBD)
What do you mean by TBD? (if you mean "to be defined", my opinion is
that this is definitely not appropriate for a Standards Track document)

2. COMMENT on section 4 page 4:
"Vendors using this new message should use the DHCPv6 security
mechanisms..."
=> maybe a SHOULD would be more appropriate in this case.

3. Minor note: the draft has expired on Feb-2.

4. COMMENT:
And last but not least a general personal comment:
The document describes how to introduce vendor specific messages which
will be solely in the control of the vendor. These message codes and
their underlying functionality are unspecified and totally beyond IANA
or IETF control.
This can introduce basically any set of security and interoperability
problems and I am not sure how this approach will support
interoperability or would benefit the operation of the internet as a
whole. But probably the DHC WG members knows better. Still, considering
this question I wonder why this is in the status of "Standards Track"
and not "Experimental".

Best regards, Tobias

Tobias Gondrom
Sloan Fellowship 2009
London Business School
email: [email-masked]
mobile: +447521003005