[secdir] Security review of draft-ietf-rtcweb-fec-08 (was Re: Security review of draft-ietf-perc-srtp-ekt-diet-08)

Ben Campbell <ben@nostrum.com> Fri, 01 February 2019 22:49 UTC

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Date: Fri, 1 Feb 2019 16:49:03 -0600
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Cc: The IESG <iesg@ietf.org>, secdir@ietf.org, draft-ietf-rtcweb-fec.all@tools.ietf.org
To: Hilarie Orman <hilarie@purplestreak.com>
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Subject: [secdir] Security review of draft-ietf-rtcweb-fec-08 (was Re: Security review of draft-ietf-perc-srtp-ekt-diet-08)
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Please note that this review is for draft-ietf-rtcweb-fec-08, not the PERC draft referenced in the subject.



> On Feb 1, 2019, at 1:42 AM, Hilarie Orman <hilarie@purplestreak.com> wrote:
> Security Review of WebRTC Forward Error Correction Requirements
> draft-ietf-rtcweb-fec-08
> Do not be alarmed.  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 document describes the appropriate uses of FEC for web content when
> using WebRTC.  It also describes how to indicate that FEC is being used.
> The Security Considerations mention the possibility of additional network
> congestion when using FEC.  Although this can be a problem, I do not think
> it is a security issue, thus it does not belong in this section.
> There is a security-related issue wrt to FEC and encryption.  If the
> error model is that message blocks may be lost but not altered in
> transit, then FEC with encryption is fine.  But if FEC is added for
> the purpose of correcting corrupted bits in a message block, then it
> is important that FEC is done after encryption.  The draft seems to
> ignore the issue, and it also seems to recommend a processing scheme
> that would result in encryption of the FEC data.  If there is a body
> of practice for other IETF FEC protocols that explains these issues,
> an explicit reference to it in the Security Considerations would be
> very helpful.
> Hilarie