Subject: [ippm] Eric Rescorla's No Objection on draft-ietf-ippm-6man-pdm-option-09: (with COMMENT)

From: Eric Rescorla <[email-masked]>
Date: Tue, 11 Apr 2017 17:11:07 -0700

Eric Rescorla has entered the following ballot position for
draft-ietf-ippm-6man-pdm-option-09: No Objection

When responding, please keep the subject line intact and reply to all
email addresses included in the To and CC lines. (Feel free to cut this
introductory paragraph, however.)

Please refer to https://www.ietf.org/iesg/statement/discuss-criteria.html
for more information about IESG DISCUSS and COMMENT positions.

The document, along with other ballot positions, can be found here:
https://datatracker.ietf.org/doc/draft-ietf-ippm-6man-pdm-option/

----------------------------------------------------------------------
COMMENT:
----------------------------------------------------------------------

I think the description of timing attacks could use a bit more work.
Specifically:

- I am assuming that you should discard rather than using as timestamp
  sources packets which fail ESP. This shouldn't be an issue for
  transport mode because you process ESP first, but in tunnel mode
  you allow either order, so it's a potential issue.

- It seems like you could use this technique for fine-grained
  timing of the cryptographic operations traffic keys as well (cf. Lucky
13),
  not just long-term keys as you say in S 4.4.

Note that both of these attacks are not ameliorated by restricting
to host and ports because one assumes that the attacker controls
the network per 3552.