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Re: [TLS] Prohibiting SSL 3.0

Florian Weimer <fw@deneb.enyo.de> Wed, 29 October 2014 11:19 UTC

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From: Florian Weimer <fw@deneb.enyo.de>
To: Hubert Kario <hkario@redhat.com>
References: <BLU177-W4981235CC3AA2325B8CC01C39F0@phx.gbl> <877fzka1bf.fsf@mid.deneb.enyo.de> <5997229.rIz4Dkd6bP@pintsize.usersys.redhat.com>
Date: Wed, 29 Oct 2014 12:18:58 +0100
In-Reply-To: <5997229.rIz4Dkd6bP@pintsize.usersys.redhat.com> (Hubert Kario's message of "Wed, 29 Oct 2014 11:43:58 +0100")
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Subject: Re: [TLS] Prohibiting SSL 3.0
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* Hubert Kario:

> On Tuesday 28 October 2014 12:19:48 Florian Weimer wrote:
>> * Yuhong Bao:
>> > I hope that a Internet-Draft prohibiting SSL 3.0 will be next.
>> 
>> RFC 6101 already has status “HISTORIC”.  I'm not sure what else the
>> IETF can do.  The cryptographically protected version negotation means
>> that there is no actual harm in supporting SSL 3.0 along with TLS.
>> (Same for supporting earlier TLS versions.)
>
> Even the TLS 1.3 draft says that a client SHOULD NOT send a SSLv2 compatible 
> client hello with server support being stated as MAY. Similarly, the value for 
> SSL 3.0 for record layer in client hello is mentioned as the backwards 
> compatible option with no mention of recommendation against it.
>
> I'd say an RFC that updates them to a MUST NOT/SHOULD NOT (respectively for 
> SSLv2 and SSLv3, at the very least) is not entirely out of scope...

I think the SSLv2 compatible client hello is unrelated to the protocol
version advertised by the client, but I might be mistaken about that.

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