Re: [TLS] SCSVs and SSLv3 fallback

[[e-mail] (Martin Rex)]

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.


-Martin