On Fri, May 1, 2020 at 4:43 PM Keith Moore <[email protected]>
wrote:

> On 5/1/20 6:48 PM, Eric Rescorla wrote:
>
> On Thu, Apr 30, 2020 at 7:59 PM Keith Moore <[email protected]>
> wrote:
>
>> People do not always have the luxury of upgrading their clients and
>> servers to versions that support the recent TLS.    Some legacy hardware
>> has firmware that cannot be upgraded because no upgrades are
>> available.   Service providers do not always have the leverage to insist
>> that their customers upgrade, or the luxury of abandoning customers. etc.
>>
>
> Somewhat tangentially from the topic at hand: if you are running a piece
> of hardware that cannot upgrade its TLS stack at all, you quite likely have
> a number of serious unpatched vulnerabilities, and should reconsider
> whether it is safe to have that hardware attached to the Internet. Of
> course, you might be running some ESR software where you can only take
> security releases, in which case this does not apply.
>
> Quite often the issue is not the hardware, but the lack of support.  In my
> experience, many appliances with IP interfaces have no long-term support to
> fix security issues, because (for various reasons) there's no revenue
> stream to support it, and there was never any plan to provide long-term
> support.   But the problem is even deeper than that - customers expect to
> pay for the product up front and little if anything for ongoing support.
> Even if the vendor wanted to sell the long term support contract there's
> little chance that the customer would pay for it.  (I'm thinking industrial
> markets here, but consumer hardware often has similar issues.)
>
> (And sometimes the compilers, linkers, etc. needed to build a new version
> of the device firmware are not easily found, and sometimes those tools
> don't run on newer operating systems, so upgrading these platforms can be
> much more complicated than just updating the source code and recompiling.)
>
Sure. I'm certainly aware of these issues. I'm merely observing that those
people probably have bigger problems than modern systems not talking to
them.

I also think it's odd that there are recommendations like this that say
>> "don't support TLS x.y" but say nothing about not supporting cleartext
>> for protocols that still have a cleartext mode.  Even SSL 1.0 is
>> probably better than cleartext (at least from a security perspective, if
>> not from a support burden perspective) as long as it's not trusted to be
>> secure.
>>
>
> While perhaps technically true, for the reasons above I believe this to be
> irrelevant: TLS 1.2 is nearly 12 years old. At this point, any
> implementation which does not support it should be presumed to be insecure
> regardless of our opinion on the specific protocols it supports.
>
> I agree that such devices are likely insecure, but there are still devices
> in service that only speak TLS 1.0 or 1.1.   Are we going to insist that no
> standards-conforming peer programs should be able to communicate with
> them?
>
That is precisely what we do for SSLv2 and SSLv3, and is in fact what the
TLS WG currently is proposing (
https://datatracker.ietf.org/doc/draft-ietf-tls-oldversions-deprecate/) so
I would advise you to keep your eye out for the IETF LC on a mailing list
near you.

-Ekr
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