Re: [mailop] self-signed cert for inbound TLS

2017-07-31 Thread Luis E. Muñoz
On 31 Jul 2017, at 19:55, John Levine wrote: Other than the usual horrible problems getting certs installed and configured, it's a great way to do client authentication. +1 Specially when you manage your own CA and can issue your own certs to the clients at onboarding. -lem _

Re: [mailop] self-signed cert for inbound TLS

2017-07-31 Thread John Levine
In article you write: >If someone connects to you, they don't send you a cert unless you're >dealing with client certs, and I don't think >DANE covers that at all, though I haven't read through it completely. The client can present a cert in the TLS handshake if it wants to. Few do and equally f

Re: [mailop] self-signed cert for inbound TLS

2017-07-29 Thread Grant Taylor via mailop
On 07/28/2017 03:19 PM, Brandon Long via mailop wrote: > If someone connects to you, they don't send you a cert unless you're > dealing with client certs, and I don't think DANE covers that at all, > though I haven't read through it completely. It's my understanding that DANE covers client certs

Re: [mailop] self-signed cert for inbound TLS

2017-07-28 Thread Brandon Long via mailop
That's a good point. The number is only for encrypted, not authenticated and it looks like we don't currently log verification. We do CA verification and a GSuite domain can choose to require it for a connection, but we don't use the information generally. Presumably when we finish our STS and DA

Re: [mailop] self-signed cert for inbound TLS

2017-07-28 Thread Michael Orlitzky
On 07/28/2017 05:19 PM, Brandon Long wrote: > > We're hovering at 88% encrypted, inbound & outbound, if those in charge > decided to move the needle, they could > probably start a path along the likes of what Chrome is doing > (https://security.googleblog.com/2016/09/moving-towards-more-secure-w

Re: [mailop] self-signed cert for inbound TLS

2017-07-28 Thread Brandon Long via mailop
On Fri, Jul 28, 2017 at 5:58 AM, Michael Orlitzky wrote: > On 07/27/2017 01:44 PM, Dave Warren wrote: > >> > >> "Even if it were generally possible to determine a secure server name, > >> the SMTP client would still need to verify that the server's > >> certificate chain is issued by a trusted CA

Re: [mailop] self-signed cert for inbound TLS

2017-07-28 Thread Grant Taylor via mailop
On 07/28/2017 02:10 AM, Vittorio Bertola wrote: On the Web, instead, users do want to know which company is actually running the website that they are visiting, and not just that they are really connecting to that hostname, so CAs offer additional value in respect to DANE. Full STOP! I disag

Re: [mailop] self-signed cert for inbound TLS

2017-07-28 Thread John Levine
In article <808816365.710.1501249729...@appsuite.open-xchange.com> you write: >> The practical reason is that unencrypted SMTP has to work if you want to >> be able to communicate with the world. ... >This, by the way, is another advantage of DANE. By publishing a TLSA record >for the ser

Re: [mailop] self-signed cert for inbound TLS

2017-07-28 Thread Grant Taylor via mailop
On 07/28/2017 06:58 AM, Michael Orlitzky wrote: If someone connects to me and I don't like his CA, he can fall back to plain text and I have to allow it (because of the bajillions of people who don't do TLS over SMTP at all). I disagree. You do have the choice to not accept messages over an u

Re: [mailop] self-signed cert for inbound TLS

2017-07-28 Thread Vittorio Bertola
> Il 28 luglio 2017 alle 14.58 Michael Orlitzky ha scritto: > > The practical reason is that unencrypted SMTP has to work if you want to > be able to communicate with the world. So, adding a second more-secure > channel *in addition to* the existing unsecured channel doesn't really >

Re: [mailop] self-signed cert for inbound TLS

2017-07-28 Thread Michael Orlitzky
On 07/27/2017 01:44 PM, Dave Warren wrote: >> >> "Even if it were generally possible to determine a secure server name, >> the SMTP client would still need to verify that the server's >> certificate chain is issued by a trusted CA (a trust anchor). >> > > I've never understood why this is a speci

Re: [mailop] self-signed cert for inbound TLS

2017-07-28 Thread Vittorio Bertola
> Il 27 luglio 2017 alle 23.48 Brandon Long via mailop ha > scritto: > > Well, yes, that is the DANE argument in a nutshell. That doesn't mean > it's correct, and there are reasons why DANE was not the solution chosen for > the browser market. > Can I ask which ones? I thought it was m

Re: [mailop] self-signed cert for inbound TLS

2017-07-27 Thread Brandon Long via mailop
On Thu, Jul 27, 2017 at 9:05 AM, Vittorio Bertola < vittorio.bert...@open-xchange.com> wrote: > > Il 26 luglio 2017 alle 19.10 Brandon Long ha scritto: > > Why can't smtp software being expected to maintain a list of trusted CAs? > Or at least run on an OS that is expected to do so. > > There is

Re: [mailop] self-signed cert for inbound TLS

2017-07-27 Thread Brandon Long via mailop
On Thu, Jul 27, 2017 at 11:32 AM, Grant Taylor via mailop wrote: > On 07/27/2017 11:44 AM, Dave Warren wrote: > >> I've never understood why this is a special challenge in the SMTP world, >> it's generally a solved problem for HTTPS, XMPP, and various other >> protocols. >> > > It's my understand

Re: [mailop] self-signed cert for inbound TLS

2017-07-27 Thread Phil Pennock
On 2017-07-25 at 22:10 -0400, Eric Tykwinski wrote: > Sorry, probably straying from the topic, but does anyone know any good SMTP > tests for DANE. > I’m using https://dane.sys4.de/ currently and it works, but I would like > something with some more details if possible. Self-pimping: https://

Re: [mailop] self-signed cert for inbound TLS

2017-07-27 Thread Grant Taylor via mailop
On 07/27/2017 11:44 AM, Dave Warren wrote: I've never understood why this is a special challenge in the SMTP world, it's generally a solved problem for HTTPS, XMPP, and various other protocols. It's my understanding that the problem has to do with the (lack of) people involved in the transact

Re: [mailop] self-signed cert for inbound TLS

2017-07-27 Thread Dave Warren
On Thu, Jul 27, 2017, at 09:05, Vittorio Bertola wrote: > >> Il 26 luglio 2017 alle 19.10 Brandon Long ha scritto:>> >> Why can't smtp software being expected to maintain a list of trusted CAs? >> Or at least run on an OS that is expected to do so.> There is a standard >> explanation (liter

Re: [mailop] self-signed cert for inbound TLS

2017-07-27 Thread Vittorio Bertola
> Il 26 luglio 2017 alle 19.10 Brandon Long ha scritto: > > Why can't smtp software being expected to maintain a list of trusted CAs? > Or at least run on an OS that is expected to do so. > There is a standard explanation (literally) in RFC 7672, section 1.3, and especially 1.3.4.: "Ev

Re: [mailop] self-signed cert for inbound TLS

2017-07-26 Thread Eric Tykwinski
> On Jul 26, 2017, at 5:42 PM, Steve Atkins wrote: > > It doesn't _really_ matter in the context of deciding whether a certificate > is being presented by a legitimate domain owner or a MitM. Well I think that’s the whole solution of DANE, ie validate through DNSSCEC that the owner of the doma

Re: [mailop] self-signed cert for inbound TLS

2017-07-26 Thread Steve Atkins
> On Jul 26, 2017, at 1:43 PM, valdis.kletni...@vt.edu wrote: > > On Wed, 26 Jul 2017 10:10:53 -0700, Brandon Long via mailop said: >> Why can't smtp software being expected to maintain a list of trusted CAs? >> Or at least run on an OS that is expected to do so. > > Quick: What two CAs did Goog

Re: [mailop] self-signed cert for inbound TLS

2017-07-26 Thread Brandon Long via mailop
If it becomes important, I'm sure it can be done. I mean, you all update your av signatures at least daily, or your spam rules. And whether they would need to follow the browser list or whatever isn't clear, sure. It's early in this stuff for email, maybe DANE will be the solution that catches o

Re: [mailop] self-signed cert for inbound TLS

2017-07-26 Thread valdis . kletnieks
On Wed, 26 Jul 2017 10:10:53 -0700, Brandon Long via mailop said: > Why can't smtp software being expected to maintain a list of trusted CAs? > Or at least run on an OS that is expected to do so. Quick: What two CAs did Google just remove from Chrome's list? Has your OS vendor followed suit? And

Re: [mailop] self-signed cert for inbound TLS

2017-07-26 Thread Luis E. Muñoz
I think the key part is not "expect", but actually don't require it. -lem On 26 Jul 2017, at 10:10, Brandon Long via mailop wrote: > Why can't smtp software being expected to maintain a list of trusted CAs? > Or at least run on an OS that is expected to do so. __

Re: [mailop] self-signed cert for inbound TLS

2017-07-26 Thread Brandon Long via mailop
On Wed, Jul 26, 2017 at 1:23 AM, Vittorio Bertola < vittorio.bert...@open-xchange.com> wrote: > > Il 25 luglio 2017 alle 22.25 Grant Taylor via mailop ha scritto: > > > On 07/25/2017 09:14 AM, Vladimir Dubrovin via mailop wrote: > > To protect against passive Man-in-the-Middle, there is no actual

Re: [mailop] self-signed cert for inbound TLS

2017-07-26 Thread Vittorio Bertola
> Il 25 luglio 2017 alle 22.25 Grant Taylor via mailop ha scritto: > > > On 07/25/2017 09:14 AM, Vladimir Dubrovin via mailop wrote: > > > > To protect against passive Man-in-the-Middle, there is no actual > > difference between the self-signed certificate and certificate fr

Re: [mailop] self-signed cert for inbound TLS

2017-07-25 Thread Eric Tykwinski
> On Jul 25, 2017, at 7:46 PM, Brandon Long via mailop > wrote: > > Agreed that STS and DANE are the solution for enforcing, however it's still > early days for those. > > Brandon Sorry, probably straying from the topic, but does anyone know any good SMTP tests for DANE. I’m using https://

Re: [mailop] self-signed cert for inbound TLS

2017-07-25 Thread Brandon Long via mailop
On Tue, Jul 25, 2017 at 4:13 PM, Ted Cabeen wrote: > On 7/25/2017 8:14 AM, Vladimir Dubrovin via mailop wrote: > >> STARTTLS is opportunistic and doesn't protect against active >> Man-in-the-Middle. In case of TLS problems it falls back to plain text. >> > > Interestingly, that's not always the c

Re: [mailop] self-signed cert for inbound TLS

2017-07-25 Thread Ted Cabeen
On 7/25/2017 8:14 AM, Vladimir Dubrovin via mailop wrote: STARTTLS is opportunistic and doesn't protect against active Man-in-the-Middle. In case of TLS problems it falls back to plain text. Interestingly, that's not always the case now. We typoed the cert on one of our list servers earlier t

Re: [mailop] self-signed cert for inbound TLS

2017-07-25 Thread Grant Taylor via mailop
On 07/25/2017 09:14 AM, Vladimir Dubrovin via mailop wrote: STARTTLS is opportunistic and doesn't protect against active Man-in-the-Middle. In case of TLS problems it falls back to plain text. STARTTLS is opportunistic, but MTAs can be configured to require protected channels and to refuse ema

Re: [mailop] self-signed cert for inbound TLS

2017-07-25 Thread Vick Khera
I've not had any issues with self signed certs with TLS on SMTP. That said, lately I've been using Lets Encrypt certificates with the certbot program to manage them, and that has worked really well. The initial setup takes a little effort to do a DNS based verification since the mail hosts are not

Re: [mailop] self-signed cert for inbound TLS

2017-07-25 Thread Vladimir Dubrovin via mailop
STARTTLS is opportunistic and doesn't protect against active Man-in-the-Middle. In case of TLS problems it falls back to plain text. To protect against passive Man-in-the-Middle, there is no actual difference between the self-signed certificate and certificate from recognized CA, so, except may b