[cabfpub] OIDs for DV and OV

Mon Oct 6 19:17:11 UTC 2014

So I get the part that Chrome (and likely other browsers in the CA/B forum) don’t intend to distinguish DV and OV certs in any way. Got that. Not a point of contention. In fact, I knew that when I started this thread.  So no need to go down that path anymore. Having different OIDs does not oblige a browser do anything. 

I would have expected more negative commentary from CAs but so far there has been none. And only 1 browser has chimed in.

However, browsers are not the only application that use SSL certificates. There are others out there and I distinctly recall a conversation about 2-3 years ago where Paypal (a CA/B member) explicitly asked that these OIDs be mandatory. Brad stated that their security group had deemed DV certs to be a security threat to their ecosystem and wanted an easy programmatic way to distinguish them. At the time, there was some pushback (I don’t believe from browsers) and the OIDs ended up being optional. 

It looks as if some CAs do use OIDs in their DV and OV certs but some don’t use the CA/B Forum OIDs (rather their own). This makes it difficult to apply a uniform decision process. 

Certs conforming to policy and issued correctly are one aspect that some folks are looking for. The type of certificate is another. One that has not been vetted is different from one that has some vetting completed (other security issues being equal). Perhaps that benefit is not tangible to some but it certainly is to others. I can spew some stats on DV cert use and fraud but that will just muddle this thread so I’ll save it for another day. 

Why do browsers care one way or the other if other parties want to make this distinction? The CA/B Forum has defined different baseline standards for these types of certs. Why not make transparency around those standards easy for those that want to draw a distinction?

Certainly would love to hear from some other interested parties.

Thanks,

Dean

From: Ryan Sleevi [mailto:sleevi at google.com] 
Sent: Thursday, October 02, 2014 8:56 PM
To: Dean Coclin
Cc: public at cabforum.org
Subject: Re: [cabfpub] OIDs for DV and OV

On Thu, Oct 2, 2014 at 5:31 PM, Dean Coclin <Dean_Coclin at symantec.com> wrote:

Thanks for the response and pointers. I’ve read through the threads but still have additional questions/comments. I’ll readily admit that I don’t understand all the commentary in the Mozilla threads so I apologize if these questions sound somewhat naïve. Happy to be educated:

You've heard repeatedly from several browsers about an explicit non-goal of distinguishing DV and OV. As the Forum is comprised of CAs and Browsers, do we have any Browsers that wish to make such a distinction? If not, it would be wholly inappropriate for the Forum to require it.

>>I haven’t heard of any browsers that want to make that distinction (yet). It is my understanding that the Forum BRs do require an OID for EV certs. So why is it “inappropriate” for the Forum to require OIDs for DV/OV?

Browsers have agreed to make a distinction between EV and !EV, so have required there be a way to detect that.

Browsers have not agreed that there is a distinction between DV or OV, nor is there a need to detect the difference.

That the browsers have required (effectively all stores at this point, AFAIK) is that the root program members be BR compliant. So any new certs issued (technically, independent of the notBefore, and we know CAs regularly backdate from time of issuance, but it's a rough heuristic) are, by definition, BR compliant.

If there are non-browser relying parties interested in such distinctions, the CA can always provide such distinctions themselves.

>>Can you elaborate on what you mean by this? If there’s another way to accomplish the end result, happy to explore further. But it would have to be uniform among all CAs that issue these certs.

I don't see why it needs to be uniform.

The requirement as to what shape it takes is dictated by the relying party applications.

The browsers, as relying party applications, do not and have not yet cared about the shape of DV and OV, and as per our recent F2F, aren't really keen to either.

So having the browsers dictate the shape of the solution seems unnecessary, and an issue for these relying party applications (e.g. Netcraft) to work with CAs.

As someone very keen on programatic checks and detection for misissuance, there's no question that this would NOT meaningfully help address the concerns we see.

>>I wasn’t suggesting that this addition would in any way help you with your programmatic checks for mis-issuance.  Rather, it would make the task for organizations like Netcraft, EFF or others that tabulate statistics on various types of certificates easier to do. Is that not the case?

Not really. These organizations are interested in the same discussions and distinctions we are - what are the certificates being issued and do they conform to the policies that they're supposed to.

We've established that there's no 'uniform' definition of what constitutes OV, only that the BR requires certain vetting steps for certain subject fields that are OPTIONAL. CAs have taken these and marketed them as OV, but there's no such distinction as a level, nor a particular profile spelled out in the appendices as to what constitutes a "DV" vs "OV".

If that was the only degree of distinction required, it's just as easy as checking the Subject fields for any of the OPTIONAL fields.

That is, there would need to be an OID _per revision_ of the BRs, to indicate "which" version of the BRs something was complying to. 

>>Fully admit that I don’t understand how this works. But wouldn’t that also be the case for EV (which currently requires this OID)?

YES! And it's one of the many reasons why EV is somewhat muddled for programatic checks or distinctions. And yet this is also necessary because any change in policy, by definition, necessitates a change in OID to (meaningfully) reflect that. And that constitutes rolling a new hierarchy (and updating browsers' lists of recognized EV OIDs)

I’m just trying to suggest a  way that someone can say: X is a DV cert, Y is an OV cert, Z is an EV cert without a doubt. If OIDs are not the place to do that, is there another mechanism available?
I’m sure you are familiar with Ryan Hurst’s blog on how difficult the task currently is.

I am (you're talking about http://unmitigatedrisk.com/?p=203 in particular). But I'm also not supportive of encouraging a distinction that we neither recognize nor have plans to recognize, and especially not supportive of mandating such distinctions.

This is especially true, as these distinctions don't offer any tangible security benefits to the Web, as previously discussed.

If we go to the point of mandating anything additional in certificates, which requires a variety of changes in processes, profiles, and CPSes, I want it to have meaningful security value. This change - which, as has been shown by the development of audit standards and then the eventual incorporation of those audit standards into the root programs, and then FINALLY the enforcement of those audit standards of the root programs - would take several years, at BEST, to deploy, and would communicate nothing of actionable value. It's a hard sell.

Thanks,
Dean

From: public-bounces at cabforum.org [mailto:public-bounces at cabforum.org] On Behalf Of Ryan Sleevi
Sent: Thursday, October 02, 2014 3:37 PM
To: Dean Coclin
Cc: public at cabforum.org
Subject: Re: [cabfpub] OIDs for DV and OV

On Thu, Oct 2, 2014 at 10:33 AM, Dean Coclin <Dean_Coclin at symantec.com> wrote:

Further to today’s discussion on our call, I’d like to get more feedback on a proposal to make a unique standardized OID mandatory for DV and OV certificates in the Baseline Requirements. Currently we have a mandatory OID for EV certificates but optional for OV and DV.  This makes things difficult for at least two groups of constituents:

1.       Relying parties that would like to distinguish between these certificates

You've heard repeatedly from several browsers about an explicit non-goal of distinguishing DV and OV. As the Forum is comprised of CAs and Browsers, do we have have any Browsers that wish to make such a distinction?

If not, it would be wholly inappropriate for the Forum to require it. If there are non-browser relying parties interested in such distinctions, the CA can always provide such distinctions themselves.

2.       Analysts that report on SSL certificate data who have had to issue revised reports because of cert misclassification

As mentioned on the call, this has been discussed with Mozilla in the past - https://groups.google.com/d/msg/mozilla.dev.security.policy/-mCAK5zfhFQ/hEOQK-ubGRcJ

As someone very keen on programatic checks and detection for misissuance, there's no question that this would NOT meaningfully help address the concerns we see.

That is, there would need to be an OID _per revision_ of the BRs, to indicate "which" version of the BRs something was complying to. 

I would hope that https://groups.google.com/d/msg/mozilla.dev.security.policy/-mCAK5zfhFQ/2tRUS444krwJ would capture some of these concerns more fully.

Finally, to do anything meaningful with this in all major clients, it would require that CAs redo their certificate hierarchy, as policy OIDs are inherited. That's a silly thing, especially when CAs are still struggling to migrate from SHA-1 to SHA-256 in their intermediates.

My proposal is for CAs to put in OID X if it’s a DV certificate and OID Y if it’s an OV certificate.

As Rick reminded me on the call, we currently have something like this for EV certificates (except that CAs are free to use the standard OID or define one of their own).

I’d like to hear pros/cons of this. Ryan S indicated that Google would not support such a proposal but we didn’t have time to discuss the reasons.

I’m sure there are both technical and policy reasons. Personally I’d like to focus on the latter but remarks on both are welcome. This proposal doesn’t require anyone to do anything with this data (i.e relying parties can choose whether or not to utilize it).

Thanks,
Dean

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