Subject: [secdir] Secdir review of draft-ietf-roll-trickle-mcast-05

From: Tero Kivinen <[email-masked]>
Date: Thu, 21 Nov 2013 14:27:39 +0200

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 describes the Multicast protocol for Low and Lossy
Networks. This protocol uses trickle algorithm. I am not familiar
enough to trickle to really analyze what the protocol does. Security
considerations section mentions that the protocol uses sequence
numbers to keep track of messages, and attacker who can insert
messages can mess up with those sequence numbers, and attacker can
then flush messages from the buffered messages list, and can also
allow setting it high enough so recipients will not get any messages
as they have too small sequence number.

The protocol has no protection against this attack, but notes that
both of those are denial-of-service attacks and devices can protect
against them by using link-layer security mechanisms. It also claims
that those mechanisms are typically employed without specifying which
security methods it is pointing to. I do not know how often those
link-layer security methods are really used. Perhaps it would be
useful to list some of those security methods here.

I do not have any other comments for the protocol, and otherwise I
think the document is ready, but as I said I did not have time to
really analyze the protocol itself.
-- 
[email-masked]

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From: Michael Richardson <[email-masked]>
Date: Tue, 26 Nov 2013 19:57:13 -0500

> ongoing effort to review all IETF documents being processed by the

Thank you.

    > as they have too small sequence number.

All correct observations.

    > useful to list some of those security methods here.

At this pointin LLNs, use of layer-2 security *ONLY* is pretty much 100%.
It's "WEP" == Wired Equivalent Privacy.

No layer-3, no other authorization distinction between devices, etc.

(Zigbee IP sometimes uses per-link keying as well, so it also defends against
nodes inside the tent going corrupt)

--
]               Never tell me the odds!                 | ipv6 mesh networks [
]   Michael Richardson, Sandelman Software Works        | network architect  [
]     [email-masked]  http://www.sandelman.ca/        |   ruby on rails    [

--
Michael Richardson <[email-masked]>, Sandelman Software Works
IETF ROLL WG co-chair.    http://datatracker.ietf.org/wg/roll/charter/

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From: Donald Eastlake <[email-masked]>
Date: Tue, 26 Nov 2013 22:51:46 -0500

Hi,

On Tue, Nov 26, 2013 at 7:57 PM, Michael Richardson
<[email-masked]> wrote:
>     > ...
>...

Are you talking about 802.11 WEP?

To quote from IEEE Std 802.11-2012: "The use of WEP for
confidentiality, authentication, or access control is deprecated. The
WEP algorithm is unsuitable for the purposes of this standard." As
they say, WEP is a digital security standard that was designed by
excellent radio engineers...

Thanks,
Donald
=============================
 Donald E. Eastlake 3rd   +1-508-333-2270 (cell)
 155 Beaver Street, Milford, MA 01757 USA
 [email-masked]

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---

From: Michael Richardson <[email-masked]>
Date: Wed, 27 Nov 2013 08:41:24 -0500

> Are you talking about 802.11 WEP?

No. I'm using a generic term.
It's like WEP == if a host has the key, it can do anything, assume any role
with any authority it likes.