Re: [TLS] draft-rescorla-tls-renegotiate and MITM resistance

Yair Elharrar <Yair.Elharrar@audiocodes.com> Mon, 09 November 2009 19:46 UTC

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From: Yair Elharrar <Yair.Elharrar@audiocodes.com>
To: David-Sarah Hopwood <david-sarah@jacaranda.org>, "tls@ietf.org" <tls@ietf.org>
Date: Mon, 09 Nov 2009 21:47:42 +0200
Thread-Topic: [TLS] draft-rescorla-tls-renegotiate and MITM resistance
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Subject: Re: [TLS] draft-rescorla-tls-renegotiate and MITM resistance
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David-Sarah Hopwood wrote:
>Marsh Ray wrote:
>> Yair Elharrar wrote:
>>> In addition, until such time that all clients in the world start
>>> supporting this extension (e.g. kiosks in airports), servers will
>>> have to support backward compatibility.
>>
>> It will be a trade-off for each server admin to weigh and decide their
>> policy. I suspect many admins will prefer not to allow insecure
>> connections from unpatched airport kiosks.
>
> To prevent this attack, they don't have to disallow connections, only
> renegotiations in which the extension is not used.
>

That's a very good point. Perhaps the draft could be changed to reflect that?
I can't see any reason why an airport kiosk would need to renegotiate an HTTPS connection (these devices rarely have client certificates installed); however it should be allowed to connect to secure web sites.

           Yair

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