Re: [rtcweb] STUN for keep-alive
Randell Jesup <randell-ietf@jesup.org> Mon, 19 September 2011 17:37 UTC
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Date: Mon, 19 Sep 2011 13:36:32 -0400
From: Randell Jesup <randell-ietf@jesup.org>
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Subject: Re: [rtcweb] STUN for keep-alive
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On 9/19/2011 10:39 AM, Magnus Westerlund wrote: > Hi, > > As an individual I like to provide some analyze of the entropy in > RTP/RTCP. Please consider, comment and provide opinion about the number > of bits. Thanks for the excellent analysis, Magnus. > On 2011-09-16 20:30, Eric Rescorla wrote: >>> The RTCP receiver reports should be adequate for 'consent freshness', no? >>> If I still like receiving the traffic, I'll report that I'm receiving it. >>> If I have crashed or disconnected or am not listening on that port, I won't. >> I believe so, though I'd have to make sure there's enough entropy. And of course >> some implementations may not do RTCP... >> > So one case of attack is the one when the webserver S uses the connected > clients to attack target T by instructing client C to send to target T. > So the Server or some server controlled entity A needs to send RTCP to C > that makes C believe T is responding, i.e. spoofed source address that > are T's plus the content of the RTCP RR. Please note that SRTP will not > provide any protection if the webserver knows the key. Thus if security > description is allowed, which appear reasonable if supporting legacy is > the goal, which is the reason for this whole proposal. I would disagree with one aspect of that: I don't know that we need to support SDES, and if we do, we only need to support it for "legacy" connections, not true webrtc browser-to-browser connections, which I assert should always be DTLS. Of course, non-encrypted RTP to a legacy device would have no protection against spoofing of return RTCP at all. Note that we need to complete a valid ICE exchange with the target per the current spec, so T can only be attacked to begin with if the ICE exchange can be spoofed. The original scenario from Eric was about "how do I determine if the recipient wants to *continue* to receive data after a valid exchange (for example after ending the call or rebooting/crashing). I haven't checked the properties of ICE and the ability to spoof it, but before analyzing the entropy required to attack the return RTCP 'freshness' state, we need to show that the attack could be begun, or state that ICE is not mandatory for some connections. As you mention, if we need extra entropy it might be possible to add it, but not if we are assuming that the other side is a legacy SDES device. -- Randell Jesup randell-ietf@jesup.org
- [rtcweb] STUN for keep-alive Christer Holmberg
- Re: [rtcweb] STUN for keep-alive Muthu Arul Mozhi Perumal (mperumal)
- Re: [rtcweb] STUN for keep-alive Christer Holmberg
- Re: [rtcweb] STUN for keep-alive Muthu Arul Mozhi Perumal (mperumal)
- Re: [rtcweb] STUN for keep-alive Christer Holmberg
- Re: [rtcweb] STUN for keep-alive Muthu Arul Mozhi Perumal (mperumal)
- Re: [rtcweb] STUN for keep-alive Christer Holmberg
- Re: [rtcweb] STUN for keep-alive Jonathan Lennox
- Re: [rtcweb] STUN for keep-alive Randell Jesup
- Re: [rtcweb] STUN for keep-alive sisalem
- Re: [rtcweb] STUN for keep-alive Magnus Westerlund
- Re: [rtcweb] STUN for keep-alive Harald Alvestrand
- Re: [rtcweb] STUN for keep-alive Eric Rescorla
- Re: [rtcweb] STUN for keep-alive Christer Holmberg
- Re: [rtcweb] STUN for keep-alive Göran Eriksson AP
- Re: [rtcweb] STUN for keep-alive Eric Rescorla
- Re: [rtcweb] STUN for keep-alive Dan Wing
- Re: [rtcweb] STUN for keep-alive Dan Wing
- Re: [rtcweb] STUN for keep-alive Dzonatas Sol
- Re: [rtcweb] STUN for keep-alive Eric Rescorla
- Re: [rtcweb] STUN for keep-alive Dan Wing
- Re: [rtcweb] STUN for keep-alive Dzonatas Sol
- Re: [rtcweb] STUN for keep-alive Harald Alvestrand
- Re: [rtcweb] STUN for keep-alive - RTCP-less appl… Olle E. Johansson
- Re: [rtcweb] STUN for keep-alive - RTCP-less appl… Hadriel Kaplan
- Re: [rtcweb] STUN for keep-alive - RTCP-less appl… Olle E. Johansson
- Re: [rtcweb] STUN for keep-alive - RTCP-less appl… Hadriel Kaplan
- Re: [rtcweb] STUN for keep-alive Magnus Westerlund
- [rtcweb] consent freshness [was RE: STUN for keep… Dan Wing
- Re: [rtcweb] consent freshness [was RE: STUN for … Magnus Westerlund
- Re: [rtcweb] consent freshness [was RE: STUN for … Dan Wing
- Re: [rtcweb] consent freshness [was RE: STUN for … Eric Rescorla
- Re: [rtcweb] consent freshness [was RE: STUN for … Muthu Arul Mozhi Perumal (mperumal)
- Re: [rtcweb] STUN for keep-alive Randell Jesup
- Re: [rtcweb] consent freshness [was RE: STUN for … Magnus Westerlund
- Re: [rtcweb] STUN for keep-alive Magnus Westerlund
- Re: [rtcweb] STUN for keep-alive - RTCP-less appl… Iñaki Baz Castillo
- Re: [rtcweb] STUN for keep-alive - RTCP-less appl… Magnus Westerlund
- Re: [rtcweb] STUN for keep-alive - RTCP-less appl… Hadriel Kaplan
- Re: [rtcweb] STUN for keep-alive - RTCP-less appl… Magnus Westerlund
- Re: [rtcweb] STUN for keep-alive - RTCP-less appl… Hadriel Kaplan
- Re: [rtcweb] STUN for keep-alive - RTCP-less appl… Colin Perkins
- Re: [rtcweb] STUN for keep-alive - RTCP-less appl… Hadriel Kaplan
- Re: [rtcweb] STUN for keep-alive - RTCP-less appl… Iñaki Baz Castillo
- Re: [rtcweb] STUN for keep-alive - RTCP-less appl… Hadriel Kaplan
- Re: [rtcweb] STUN for keep-alive - RTCP-less appl… Colin Perkins
- Re: [rtcweb] STUN for keep-alive - RTCP-less appl… Magnus Westerlund
- Re: [rtcweb] STUN for keep-alive - RTCP-less appl… Hadriel Kaplan
- Re: [rtcweb] STUN for keep-alive - RTCP-less appl… Iñaki Baz Castillo
- Re: [rtcweb] STUN for keep-alive - RTCP-less appl… Iñaki Baz Castillo
- Re: [rtcweb] consent freshness [was RE: STUN for … Muthu Arul Mozhi Perumal (mperumal)
- Re: [rtcweb] STUN for keep-alive - RTCP-less appl… Magnus Westerlund
- Re: [rtcweb] STUN for keep-alive - RTCP-less appl… Magnus Westerlund
- Re: [rtcweb] consent freshness [was RE: STUN for … Magnus Westerlund
- Re: [rtcweb] STUN for keep-alive - RTCP-less appl… Hadriel Kaplan
- Re: [rtcweb] consent freshness [was RE: STUN for … Muthu Arul Mozhi Perumal (mperumal)
- Re: [rtcweb] consent freshness [was RE: STUN for … Randell Jesup
- Re: [rtcweb] STUN for keep-alive - RTCP-less appl… Magnus Westerlund
- Re: [rtcweb] consent freshness [was RE: STUN for … Magnus Westerlund
- Re: [rtcweb] consent freshness [was RE: STUN for … Randell Jesup
- Re: [rtcweb] STUN for keep-alive Cullen Jennings
- Re: [rtcweb] STUN for keep-alive Michael Tüxen
- Re: [rtcweb] STUN for keep-alive - RTCP-less appl… Hadriel Kaplan
- Re: [rtcweb] consent freshness [was RE: STUN for … Magnus Westerlund
- Re: [rtcweb] consent freshness [was RE: STUN for … Harald Alvestrand
- Re: [rtcweb] consent freshness [was RE: STUN for … Stefan Håkansson LK
- Re: [rtcweb] STUN for keep-alive - RTCP-less appl… Olle E. Johansson
- Re: [rtcweb] STUN for keep-alive - RTCP-less appl… Iñaki Baz Castillo
- Re: [rtcweb] STUN for keep-alive - RTCP-less appl… Harald Alvestrand
- Re: [rtcweb] STUN for keep-alive - RTCP-less appl… Iñaki Baz Castillo
- Re: [rtcweb] STUN for keep-alive - RTCP-less appl… Harald Alvestrand
- Re: [rtcweb] STUN for keep-alive - RTCP-less appl… Iñaki Baz Castillo
- Re: [rtcweb] STUN for keep-alive - RTCP-less appl… Harald Alvestrand
- Re: [rtcweb] STUN for keep-alive - RTCP-less appl… Iñaki Baz Castillo