Re: [rtcweb] AVPF [was: Encryption mandate (and offer/answer)]
Randell Jesup <randell-ietf@jesup.org> Fri, 09 September 2011 21:16 UTC
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Subject: Re: [rtcweb] AVPF [was: Encryption mandate (and offer/answer)]
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On 9/9/2011 3:23 PM, Alan Johnston wrote: > Ekr is correct. If we allow RTP, which I think is a mistake, then > there is always a downgrade attack. Yes, that's true. The same issue was involved in the best-effort-srtp draft, which unfortunately was dropped because CapNeg would "solve" it. (For historical note, it's still not "solved" because CapNeg support is >>>> more complex than best-effort-srtp and not generally deployed, and I doubt ever will be ala SDPng (though I'm not close to status on CapNeg.) Hmmm. A real downgrade attack requires that the signalling be compromised. I wonder if there are characteristics of a webrtc transaction that could help avoid this sort of attack (for example, a secondary way out-of-scope here for the app to know ahead of time if the target will need to be downgraded). Or some way for the service to vouch for the downgrade (i.e. wasn't a MITM). You have to trust the service, but in this case you're doing so to this degree anyways. > My point was that if we must support insecure media, we could avoid > the complexity of CapNeg by not requiring a single pass non-secure > media negotiation. There is another option. I talked about services that wanted to support PSTN could decide if they were willing to support a downgrade. The application could know it's calling a PSTN gateway and if it does know that, avoid a media gateway by not offering encrypted media. I see a significant use-case for some services will be calling PSTN numbers and services, much as it is now for VoIP. Yes, a bunch of new non-legacy services wouldn't use/want it. But the app for a PSTN-using service could specifically allow it. So the question comes down to what's the advantage to using unencrypted RTP? 1) No media gateway needed. This is the big one. Saves on $$$, saves on delay (sometimes a lot), may save on complexity in a PBX type of situation. But is there an issue due to ICE requirements? If those can't be turned off safely too, that kills this whole discussion I think. 2) Debug/etc tools work better with RTP. Not important. 3) May simplify/improve some E911 cases. Might be important; likely not. So, effectively it comes down to "is advantage 1 worth the complexity/risk?" Anyone want to defend that case? > - Alan - > > On Fri, Sep 9, 2011 at 1:35 PM, Eric Rescorla<ekr@rtfm.com> wrote: >> Unless I'm missing something, if you (a) support an insecure mode and (b) allow >> negotiation of insecure vs. secure, there's not really any way to >> avoid a downgrade >> issue; the attacker can always pretend not to support security and how do you >> know better? Obviously, it helps if you can negotiate the use or non-use of >> media security over a secure-ish signaling channel, but that doesn't reduce >> the threat from the signaling service. >> >> Best, >> -Ekr >> -- Randell Jesup randell-ietf@jesup.org
- [rtcweb] Remote recording - RTC-Web client acting… Elwell, John
- Re: [rtcweb] Remote recording - RTC-Web client ac… Stefan Håkansson LK
- Re: [rtcweb] Remote recording - RTC-Web client ac… Ravindran Parthasarathi
- Re: [rtcweb] Remote recording - RTC-Web client ac… Paul Kyzivat
- Re: [rtcweb] Remote recording - RTC-Web client ac… Dan York
- Re: [rtcweb] Remote recording - RTC-Web client ac… Elwell, John
- Re: [rtcweb] Remote recording - RTC-Web client ac… Olle E Johansson
- Re: [rtcweb] Remote recording - RTC-Web client ac… Dan York
- Re: [rtcweb] Remote recording - RTC-Web client ac… Hutton, Andrew
- Re: [rtcweb] Remote recording - RTC-Web client ac… Igor Faynberg
- [rtcweb] SIP MUST NOT be used in browser?[was RE:… Ravindran Parthasarathi
- Re: [rtcweb] SIP MUST NOT be used in browser?[was… Igor Faynberg
- Re: [rtcweb] Remote recording - RTC-Web client ac… Randell Jesup
- Re: [rtcweb] Remote recording - RTC-Web client ac… Elwell, John
- Re: [rtcweb] Remote recording - RTC-Web client ac… Hutton, Andrew
- Re: [rtcweb] Remote recording - RTC-Web client ac… Harald Alvestrand
- Re: [rtcweb] Remote recording - RTC-Web client ac… Dzonatas Sol
- Re: [rtcweb] Remote recording - RTC-Web client ac… Igor Faynberg
- Re: [rtcweb] Remote recording - RTC-Web client ac… Paul Kyzivat
- Re: [rtcweb] Remote recording - RTC-Web client ac… Harald Alvestrand
- Re: [rtcweb] Remote recording - RTC-Web client ac… Elwell, John
- Re: [rtcweb] Remote recording - RTC-Web client ac… Matthew Kaufman
- Re: [rtcweb] Remote recording - RTC-Web client ac… Dzonatas Sol
- Re: [rtcweb] Remote recording - RTC-Web client ac… Ravindran Parthasarathi
- Re: [rtcweb] Remote recording - RTC-Web client ac… Timothy B. Terriberry
- Re: [rtcweb] Remote recording - RTC-Web client ac… Ravindran Parthasarathi
- Re: [rtcweb] Remote recording - RTC-Web client ac… Ravindran Parthasarathi
- Re: [rtcweb] Remote recording - RTC-Web client ac… Matthew Kaufman
- Re: [rtcweb] Remote recording - RTC-Web client ac… Matthew Kaufman
- Re: [rtcweb] Remote recording - RTC-Web client ac… Bernard Aboba
- Re: [rtcweb] Remote recording - RTC-Web client ac… Robert O'Callahan
- Re: [rtcweb] Remote recording - RTC-Web client ac… Robert O'Callahan
- Re: [rtcweb] Remote recording - RTC-Web client ac… Elwell, John
- Re: [rtcweb] SIP MUST NOT be used in browser?[was… Matthew Kaufman
- Re: [rtcweb] SIP MUST NOT be used in browser?[was… Igor Faynberg
- Re: [rtcweb] SIP MUST NOT be used in browser?[was… Ravindran Parthasarathi
- Re: [rtcweb] SIP MUST NOT be used in browser?[was… Matthew Kaufman
- Re: [rtcweb] SIP MUST NOT be used in browser?[was… Olle E. Johansson
- Re: [rtcweb] SIP MUST NOT be used in browser?[was… Ravindran Parthasarathi
- Re: [rtcweb] SIP MUST NOT be used in browser?[was… Asveren, Tolga
- Re: [rtcweb] SIP MUST NOT be used in browser?[was… Igor Faynberg
- Re: [rtcweb] SIP MUST NOT be used in browser?[was… Justin Uberti
- Re: [rtcweb] SIP MUST NOT be used in browser?[was… Matthew Kaufman
- Re: [rtcweb] SIP MUST NOT be used in browser?[was… Matthew Kaufman
- Re: [rtcweb] SIP MUST NOT be used in browser?[was… Matthew Kaufman
- Re: [rtcweb] SIP MUST NOT be used in browser?[was… Matthew Kaufman
- Re: [rtcweb] SIP MUST NOT be used in browser?[was… Paul Kyzivat
- Re: [rtcweb] SIP MUST NOT be used in browser?[was… Olle E. Johansson
- Re: [rtcweb] SIP MUST NOT be used in browser?[was… Roman Shpount
- Re: [rtcweb] SIP MUST NOT be used in browser?[was… Igor Faynberg
- Re: [rtcweb] SIP MUST NOT be used in browser?[was… Igor Faynberg
- Re: [rtcweb] SIP MUST NOT be used in browser?[was… Ravindran Parthasarathi
- Re: [rtcweb] SIP MUST NOT be used in browser?[was… Harald Alvestrand
- Re: [rtcweb] SIP MUST NOT be used in browser?[was… Markus.Isomaki
- Re: [rtcweb] SIP MUST NOT be used in browser?[was… Randell Jesup
- [rtcweb] Encryption mandate Randell Jesup
- Re: [rtcweb] Encryption mandate Olle E. Johansson
- Re: [rtcweb] Encryption mandate Dzonatas Sol
- Re: [rtcweb] SIP MUST NOT be used in browser?[was… Olle E. Johansson
- Re: [rtcweb] SIP MUST NOT be used in browser?[was… Olle E. Johansson
- Re: [rtcweb] Encryption mandate Dzonatas Sol
- Re: [rtcweb] Encryption mandate (and offer/answer) Jonathan Lennox
- Re: [rtcweb] Encryption mandate Christopher Blizzard
- Re: [rtcweb] Encryption mandate Igor Faynberg
- Re: [rtcweb] Encryption mandate Dzonatas Sol
- Re: [rtcweb] Encryption mandate Paul Kyzivat
- Re: [rtcweb] Encryption mandate Igor Faynberg
- Re: [rtcweb] Encryption mandate Randell Jesup
- Re: [rtcweb] SIP MUST NOT be used in browser?[was… Matthew Kaufman
- Re: [rtcweb] SIP MUST NOT be used in browser?[was… Matthew Kaufman
- Re: [rtcweb] Encryption mandate (and offer/answer) Randell Jesup
- Re: [rtcweb] Encryption mandate Matthew Kaufman
- Re: [rtcweb] Encryption mandate Randell Jesup
- Re: [rtcweb] Encryption mandate Dzonatas Sol
- Re: [rtcweb] SIP MUST NOT be used in browser?[was… Silvia Pfeiffer
- Re: [rtcweb] Encryption mandate Christopher Blizzard
- Re: [rtcweb] SIP MUST NOT be used in browser?[was… Ravindran Parthasarathi
- Re: [rtcweb] SIP MUST NOT be used in browser?[was… Ravindran Parthasarathi
- Re: [rtcweb] Encryption mandate Olle E. Johansson
- Re: [rtcweb] Encryption mandate Olle E. Johansson
- Re: [rtcweb] SIP MUST NOT be used in browser?[was… Olle E. Johansson
- Re: [rtcweb] SIP MUST NOT be used in browser?[was… Silvia Pfeiffer
- Re: [rtcweb] Encryption mandate Randell Jesup
- [rtcweb] AVPF [was: Encryption mandate (and offer… Christer Holmberg
- Re: [rtcweb] SIP MUST NOT be used in browser?[was… Harald Alvestrand
- Re: [rtcweb] SIP MUST NOT be used in browser?[was… Olle E. Johansson
- Re: [rtcweb] SIP MUST NOT be used in browser?[was… Silvia Pfeiffer
- Re: [rtcweb] Encryption mandate Michael Procter
- Re: [rtcweb] SIP MUST NOT be used in browser?[was… Tim Panton
- Re: [rtcweb] SIP MUST NOT be used in browser?[was… Olle E. Johansson
- Re: [rtcweb] AVPF [was: Encryption mandate (and o… Jonathan Lennox
- Re: [rtcweb] SIP MUST NOT be used in browser?[was… Igor Faynberg
- Re: [rtcweb] SIP MUST NOT be used in browser?[was… Tim Panton
- Re: [rtcweb] SIP MUST NOT be used in browser?[was… Igor Faynberg
- [rtcweb] Meeting Bridge and Webex link for Sept 8… Sohel Khan
- Re: [rtcweb] SIP MUST NOT be used in browser?[was… Harald Alvestrand
- Re: [rtcweb] Encryption mandate Paul Kyzivat
- Re: [rtcweb] SIP MUST NOT be used in browser?[was… Bernard Aboba
- Re: [rtcweb] SIP MUST NOT be used in browser?[was… Igor Faynberg
- Re: [rtcweb] SIP MUST NOT be used in browser?[was… Igor Faynberg
- Re: [rtcweb] SIP MUST NOT be used in browser?[was… Ravindran Parthasarathi
- Re: [rtcweb] SIP MUST NOT be used in browser?[was… Harald Alvestrand
- Re: [rtcweb] SIP MUST NOT be used in browser?[was… Ravindran Parthasarathi
- Re: [rtcweb] SIP MUST NOT be used in browser?[was… Roman Shpount
- Re: [rtcweb] AVPF [was: Encryption mandate (and o… Roman Shpount
- Re: [rtcweb] Encryption mandate Paul Kyzivat
- Re: [rtcweb] SIP MUST NOT be used in browser?[was… Paul Kyzivat
- Re: [rtcweb] SIP MUST NOT be used in browser?[was… Ravindran Parthasarathi
- Re: [rtcweb] Encryption mandate Christopher Blizzard
- Re: [rtcweb] SIP MUST NOT be used in browser?[was… Igor Faynberg
- Re: [rtcweb] SIP MUST NOT be used in browser?[was… Justin Uberti
- Re: [rtcweb] SIP MUST NOT be used in browser?[was… Peter Saint-Andre
- Re: [rtcweb] SIP MUST NOT be used in browser?[was… Igor Faynberg
- Re: [rtcweb] SIP MUST NOT be used in browser? Aaron Clauson
- Re: [rtcweb] AVPF [was: Encryption mandate (and o… Justin Uberti
- Re: [rtcweb] AVPF [was: Encryption mandate (and o… Alan Johnston
- Re: [rtcweb] AVPF [was: Encryption mandate (and o… Justin Uberti
- Re: [rtcweb] AVPF [was: Encryption mandate (and o… Matthew Kaufman
- Re: [rtcweb] AVPF [was: Encryption mandate (and o… Dzonatas Sol
- Re: [rtcweb] AVPF [was: Encryption mandate (and o… Eric Rescorla
- Re: [rtcweb] AVPF [was: Encryption mandate (and o… Justin Uberti
- Re: [rtcweb] AVPF [was: Encryption mandate (and o… Dzonatas Sol
- Re: [rtcweb] AVPF [was: Encryption mandate (and o… Alan Johnston
- Re: [rtcweb] AVPF [was: Encryption mandate (and o… Roman Shpount
- Re: [rtcweb] AVPF [was: Encryption mandate (and o… Dzonatas Sol
- Re: [rtcweb] AVPF [was: Encryption mandate (and o… Dzonatas Sol
- Re: [rtcweb] AVPF [was: Encryption mandate (and o… Christer Holmberg
- Re: [rtcweb] AVPF [was: Encryption mandate (and o… Dzonatas Sol
- Re: [rtcweb] AVPF [was: Encryption mandate (and o… Christer Holmberg
- Re: [rtcweb] AVPF [was: Encryption mandate (and o… Randell Jesup
- Re: [rtcweb] AVPF [was: Encryption mandate (and o… Justin Uberti
- Re: [rtcweb] AVPF [was: Encryption mandate (and o… Dzonatas Sol
- Re: [rtcweb] AVPF [was: Encryption mandate (and o… Dzonatas Sol
- Re: [rtcweb] AVPF [was: Encryption mandate (and o… Paul Kyzivat
- Re: [rtcweb] AVPF [was: Encryption mandate (and o… Olle E. Johansson
- Re: [rtcweb] AVPF [was: Encryption mandate (and o… Olle E. Johansson
- Re: [rtcweb] AVPF [was: Encryption mandate (and o… Olle E. Johansson
- Re: [rtcweb] AVPF [was: Encryption mandate (and o… Roman Shpount
- Re: [rtcweb] AVPF [was: Encryption mandate (and o… Matthew Kaufman
- Re: [rtcweb] AVPF [was: Encryption mandate (and o… Dzonatas Sol
- Re: [rtcweb] AVPF [was: Encryption mandate (and o… Dzonatas Sol
- Re: [rtcweb] AVPF [was: Encryption mandate (and o… Dzonatas Sol
- Re: [rtcweb] AVPF [was: Encryption mandate (and o… Dzonatas Sol
- Re: [rtcweb] AVPF [was: Encryption mandate (and o… Roman Shpount
- Re: [rtcweb] AVPF [was: Encryption mandate (and o… Matthew Kaufman
- Re: [rtcweb] AVPF [was: Encryption mandate (and o… Bernard Aboba
- Re: [rtcweb] AVPF [was: Encryption mandate (and o… Christer Holmberg
- Re: [rtcweb] AVPF [was: Encryption mandate (and o… Paul Kyzivat
- Re: [rtcweb] AVPF [was: Encryption mandate (and o… Randell Jesup
- Re: [rtcweb] AVPF [was: Encryption mandate (and o… Stefan Håkansson LK
- Re: [rtcweb] AVPF [was: Encryption mandate (and o… Hadriel Kaplan
- Re: [rtcweb] AVPF [was: Encryption mandate (and o… Timothy B. Terriberry
- Re: [rtcweb] AVPF [was: Encryption mandate (and o… Dzonatas Sol
- Re: [rtcweb] SIP MUST NOT be used in browser?[was… Ravindran Parthasarathi
- Re: [rtcweb] SIP MUST NOT be used in browser? Ravindran Parthasarathi
- Re: [rtcweb] SIP MUST NOT be used in browser?[was… Ravindran Parthasarathi
- Re: [rtcweb] AVPF [was: Encryption mandate (and o… Roman Shpount
- Re: [rtcweb] AVPF [was: Encryption mandate (and o… Roman Shpount
- Re: [rtcweb] SIP MUST NOT be used in browser?[was… Roman Shpount
- Re: [rtcweb] AVPF [was: Encryption mandate (and o… Stefan Håkansson LK
- Re: [rtcweb] AVPF [was: Encryption mandate (and o… Stefan Håkansson LK
- [rtcweb] SIP vs Websocket in RTCWeb [was RE: SIP … Ravindran Parthasarathi
- Re: [rtcweb] AVPF [was: Encryption mandate (and o… Matthew Kaufman
- Re: [rtcweb] AVPF [was: Encryption mandate (and o… Matthew Kaufman
- Re: [rtcweb] AVPF [was: Encryption mandate (and o… DRAGE, Keith (Keith)
- Re: [rtcweb] SIP MUST NOT be used in browser?[was… Muthu Arul Mozhi Perumal (mperumal)
- Re: [rtcweb] SIP vs Websocket in RTCWeb [was RE: … Peter Saint-Andre
- Re: [rtcweb] AVPF [was: Encryption mandate (and o… Paul Kyzivat
- Re: [rtcweb] SIP vs Websocket in RTCWeb [was RE: … Dzonatas Sol
- Re: [rtcweb] SIP vs Websocket in RTCWeb [was RE: … Ravindran Parthasarathi
- Re: [rtcweb] SIP MUST NOT be used in browser?[was… Ravindran Parthasarathi
- Re: [rtcweb] SIP MUST NOT be used in browser?[was… Jozsef Vass
- Re: [rtcweb] SIP MUST NOT be used in browser?[was… Roman Shpount
- Re: [rtcweb] SIP vs Websocket in RTCWeb [was RE: … Peter Saint-Andre
- [rtcweb] signaling protocol SHANMUGALINGAM SIVASOTHY
- Re: [rtcweb] AVPF [was: Encryption mandate (and o… Hadriel Kaplan
- Re: [rtcweb] AVPF [was: Encryption mandate (and o… Hadriel Kaplan
- Re: [rtcweb] SIP MUST NOT be used in browser? Tim Panton
- Re: [rtcweb] SIP MUST NOT be used in browser?[was… Tim Panton
- Re: [rtcweb] SIP MUST NOT be used in browser? Olle E. Johansson
- Re: [rtcweb] SIP MUST NOT be used in browser? Ravindran Parthasarathi
- Re: [rtcweb] SIP MUST NOT be used in browser?[was… Muthu Arul Mozhi Perumal (mperumal)
- Re: [rtcweb] AVPF [was: Encryption mandate (and o… Dan Wing
- Re: [rtcweb] AVPF [was: Encryption mandate (and o… Tim Panton
- Re: [rtcweb] AVPF [was: Encryption mandate (and o… Dan Wing