Subject: [multipathtcp] Roman Danyliw's No Objection on draft-ietf-mptcp-rfc6824bis-15: (with COMMENT)

From: Roman Danyliw via Datatracker <[email-masked]>
Date: Wed, 15 May 2019 12:31:03 -0700

Roman Danyliw has entered the following ballot position for
draft-ietf-mptcp-rfc6824bis-15: No Objection

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COMMENT:
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(1) Section 2.3.  Editorial.  s/successful reception/successful receipt/

(2) Section 5.  Thanks for mentioning the possibility of a downgrade attack in
both the protocol version and algorithm negotiation.  Since [RFC7430] spells
out a clear attacker taxonomy, I’d recommend using it here too (just like it
was used in the new text added for the downgrade attack on the version
negotiation).

Old:
Note that this would be susceptible to bid-down attacks only if the attacker
was on-path (and thus would be able to modify the data anyway).

Proposed New:
Note that this negotiation would be susceptible to a bid-down attack by an
on-path active attacker who could modify the crypto capability bits response
from the receiver to use a less secure crypto mechanism.

(3) Section 6.
> Intrusion Detection Systems look out for traffic patterns and
>     content that could threaten a network.  Multipath will mean that
>     such data is potentially spread, so it is more difficult for an
>      IDS to analyze the whole traffic, and potentially increases the
>      risk of false positives.

I’d recommend being a bit clearer on the impact to NIDS.  Perhaps something
like the following:

Intrusion Detection/Prevention Systems (IDS/IPS) observe packet streams for
patterns and content that could threaten a network.  Multipath may require the
instrumentation of additional paths and correlation of data from these paths to
maintain comparable visibility into all of the traffic between end-points. 
Without such changes, an IDS would get an incomplete view of the traffic where
by increasing the risk of missing traffic of interest and producing false
positive alerts.  MPTCP-aware IDS/IPS would need to read tokens to correlate
multiple subflows and reassemble them for analysis.