Re: [TLS] SCSVs and SSLv3 fallback

[[e-mail] (Martin Rex)]

Following up to myself.

That middlebox vendors knowledgebase article says
"Cannot access some HTTPS sites in Internet Explorer with Windows 7",
so it seems to affect connections established with TLSv1.2, not just
initial TLSv1.2 ClientHellos with TLSv1.2 at the record layer.

Sorry for the confusion.

-Martin

Martin Rex wrote:
> Geoffrey Keating wrote:
> > 
> > > I've heard (anecdotally) that HTTPS between browsers and webservers
> > > who are both TLS-capable sometimes results in SSLv3 connections.
> > > Presumably this is due to firewall interference with the TLS
> > > handshake, causing browsers to retry an SSLv3 handshake.
> > 
> > The name of one firewall which is confirmed to do this would make it a
> > lot more convincing...  It's likely that some TLS connections failed
> > due to packet loss or a busy server and so the 'fallback' was a
> > mistake.
> 
> In a different discussion I heard the name of one such middleboxes,
> one that seems to be popular in enterprises:
> 
>   https://kb.bluecoat.com/index?page=content&id=KB5493
> 
> that appears to be incompatible with _at_least_ the silly Windows SChannel
> and (former?) iPhone behaviour to use TLSv1.2 at the record layer.
> 
> I don't know whether this affected middlebox will is hostile towards
> TLSv1.2 in general, or would let pass a more reasonable record version
> "{03,01}" for a "{03,03}" ClientHello, such as is used by openssl-1.0.1.