Re: [Perc] Mirja Kühlewind's No Objection on draft-ietf-perc-private-media-framework-10: (with COMMENT)
"Paul E. Jones" <paulej@packetizer.com> Tue, 14 May 2019 23:53 UTC
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From: "Paul E. Jones" <paulej@packetizer.com>
To: Mirja Kühlewind <ietf@kuehlewind.net>, The IESG <iesg@ietf.org>, Vincent Roca <vincent.roca@inria.fr>
Cc: nohlmeier@mozilla.com, perc-chairs@ietf.org, perc@ietf.org, draft-ietf-perc-private-media-framework@ietf.org
Date: Tue, 14 May 2019 23:53:01 +0000
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Subject: Re: [Perc] Mirja Kühlewind's No Objection on draft-ietf-perc-private-media-framework-10: (with COMMENT)
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Mirja, Yeah, that is valid point. We mentioned a time or two in the document how important it is to secure the Key Distributor, but explicit text that discusses that further might be appropriate here. I've copied Vincent for his input, too, since he did have comments on other parts of the Security Considerations section. I made a first draft of a new section. I pasted it below. Please let me know what you think. Thanks, Paul 8.3. Key Distributor Attacks As stated in Section 3.2.2, the Key Distributor needs to be secured since exploiting the Key Server can allow an adversary to gain access to the keying material for one or more conferences. Having access to that keying material would then allow the adversary to decrypt media sent from any endpoint in the conference. As a first line of defense, the Key Distributor authenticates every security association, both associations with endpoints and Media Distributors. The Key Distributor knows which entities are authorized to have access to which keys and inspection of certificates will substantially reduce the risk of providing keys to an adversary. Both physical and network access to the Key Distributor should be severely restricted. This may be more difficult to achieve when the Key Distributor is embedded within and endpoint, for example. Nonetheless, consideration should be given to shielding the Key Distributor from unauthorized access or any access that is not strictly necessary for the support of an ongoing conference. Consideration should be given to whether access to the keying material will be needed beyond the conclusion of a conference. If not needed, the Key Distributor's policy should be to destroy the keying material once the conference concludes or when keying material changes during the course of the conference. If keying material is needed beyond the lifetime of the conference, further consideration should be given to protecting keying material from future exposure. While it might be obvious, it is worth stating to avoid any doubt that if an adversary were to record the media packets transmitted during a conference and then gain unauthorized access to the keying material left unsecured on the Key Distributor even years later, the adversary could decrypt the content every packet transmitted during the conference. ------ Original Message ------ From: "Mirja Kühlewind via Datatracker" <noreply@ietf.org> To: "The IESG" <iesg@ietf.org> Cc: nohlmeier@mozilla.com; perc-chairs@ietf.org; perc@ietf.org; draft-ietf-perc-private-media-framework@ietf.org Sent: 5/14/2019 7:12:07 AM Subject: [Perc] Mirja Kühlewind's No Objection on draft-ietf-perc-private-media-framework-10: (with COMMENT) >Mirja Kühlewind has entered the following ballot position for >draft-ietf-perc-private-media-framework-10: 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-perc-private-media-framework/ > > > >---------------------------------------------------------------------- >COMMENT: >---------------------------------------------------------------------- > >Thanks for this well-written document. > >Regarding the security considerations, I would think that the Key Distributor >is actually sometime like a central attack point, however, I don't think that >is really discussed in the security considerations section. Would it make sense >to add some more words there? > > >_______________________________________________ >Perc mailing list >Perc@ietf.org >https://www.ietf.org/mailman/listinfo/perc
- [Perc] Mirja Kühlewind's No Objection on draft-ie… Mirja Kühlewind via Datatracker
- Re: [Perc] Mirja Kühlewind's No Objection on draf… Paul E. Jones