Open Stack

> On Nov 22, 2014, at 1:45 AM, Robert Collins <robertc at robertcollins.net> wrote:
> 
> On 22 November 2014 08:11, Jeremy Stanley <fungi at yuggoth.org> wrote:
>> On 2014-11-21 12:31:08 -0500 (-0500), Donald Stufft wrote:
>>> Death to SSLv3 IMO.
>> 
>> Sure, we should avoid releasing new versions of things which assume
>> SSLv3 support is present in underlying libraries/platforms (it's
>> unclear to me why anyone even thought it was good to make that
>> configurable to this degree in openstack-common, but it probably
>> dates back to before the nova common split). But what we're talking
>> about here is fixing a deployability/usability bug where the
>> software is assuming the presence of something removed from a
>> dependency on some platform. I'd rather not conflate it with
>> knee-jerk "SSLv3 Bad" rhetoric which risks giving casual readers the
>> impression there's some vulnerability here.
>> 
>> Ceasing to assume the presence of SSLv3 support is a safe choice for
>> the software in question. Forcing changes to stable branches for
>> this should be taken on its merits as a normal bug, and not
>> prioritized because of any perceived security impact.
> 
> Given the persistent risks of downgrade attacks, I think this does
> actually qualify as a security issue: not that its breaking,but that
> SSLv3 is advertised and accepted anywhere.
> 
> The lines two lower:
>    try:
>        _SSL_PROTOCOLS["sslv2"] = ssl.PROTOCOL_SSLv2
>    except AttributeError:
>        pass
> 
> Are even more concerning!
> 
> That said, code like:
> https://github.com/mpaladin/python-amqpclt/blob/master/amqpclt/kombu.py#L101
> 
> is truely egregious!
> 
> :)
> 

Yes this. SSLv3 isn’t a “Well as long as you have newer things enabled it’s
fine” it’s a “If you have this enabled at all it’s a problem”. As far as I
am aware without TLS_FALLBACK_SCSV a MITM who is willing to do active attacks
can force the connection over to the lowest protocol that a client and server
support. There is no way for the server to verify that the message sent from
the client that indicates their highest was not modified in transit.

---
Donald Stufft
PGP: 7C6B 7C5D 5E2B 6356 A926 F04F 6E3C BCE9 3372 DCFA