Re: [TLS] The risk of misconfiguration

[Watson Ladd <[e-mail]>]

On Tue, May 13, 2014 at 7:22 PM, Viktor Dukhovni
<[e-mail]> wrote:
> On Wed, May 07, 2014 at 05:58:35AM +0000, Viktor Dukhovni wrote:
>
>> > Ask someone "When you send email to someone, who can
>> > read it?".
>>
>> We're talking about TLS in SMTP not who can or can't read stored
>> email.  Whether the man in the street knows it or not, a substantial
>> fraction (estimated 20% and growing) of email traffic is encrypted
>> in transit, just because both ends can simply turn on STARTTLS.
>> I bet this fraction is larger than the fraction of HTTP traffic
>> that is protected inside HTTPS.
>
> Right on queue:
>
>     https://www.facebook.com/notes/protect-the-graph/the-current-state-of-smtp-starttls-deployment/1453015901605223
>
> I was fairly sure my number of 20% was conservative, now Facebook
> measures it at 58%:
>
>     We found that 76% of unique MX hostnames that receive our emails
>     support STARTTLS. As a result, 58% of notification emails are
>     successfully encrypted. Additionally, certificate validation
>     passes for about half of the encrypted email, and the other
>     half is opportunistically encrypted. 74% of hosts that support
>     STARTTLS also provide Perfect Forward Secrecy.
>
> It is perhaps time to retire the belief that TLS for email is in
> a "sad state".  Of course it would be nice to also have authentication,
> but for that we need DNSSEC deployment and publication of TLSA RRs.

So 0% of the email is actually protected from being read by anyone on
the network. (well, modulo PGP). In another 20 years we might have a
solution deployed.

And for this you want to run the risk of using aDH?

Sincerely,
Watson Ladd