Will this permit either verification of the email address or the domain part? 
For example, some organizations may verify their entire domain space and then 
confirm contractors using a random value sent to the email address itself. They 
don't  need the entire domain space in those cases, but they do need to issue 
certificates for a few email addresses outside of their domain control. 
Verification of email control using a random value seems like it affords 
controls that are equivalent to the challenge-response mechanisms in the BRs.  

-----Original Message-----
From: dev-security-policy <dev-security-policy-boun...@lists.mozilla.org> On 
Behalf Of Wayne Thayer via dev-security-policy
Sent: Friday, October 4, 2019 2:38 PM
To: Kathleen Wilson <kwil...@mozilla.com>
Cc: mozilla-dev-security-policy <mozilla-dev-security-pol...@lists.mozilla.org>
Subject: Re: Policy 2.7 Proposal: Forbid Delegation of Email Validation for 
S/MIME Certificates

I'd like to revive this discussion. So far we've established that the existing 
"required practice" [1] is too stringent for email address validation and needs 
to be changed. We can do that by removing email addresses from the scope of the 
requirement as Kathleen proposed, or by exempting the local part of the email 
address as I proposed earlier:

"CAs MUST NOT delegate validation of the domain name part of an email address 
to a 3rd party."

We have a fairly detailed explanation from Ryan Hurst of why and how removing 
the requirement entirely is beneficial, but no one else has spoken in favor of 
this need. Kathleen did however point out that this requirement doesn't appear 
to be the result of a thorough analysis. We have Ryan Sleevi arguing that the 
process described by Ryan Hurst is insecure and thus a reason to forbid 
delegation of validation of the domain name part. Pedro Fuentes also wrote in 
favor of this outcome.

One thing that might help to resolve this is a more detailed description of the 
weaknesses that are present in the process described by Ryan Hurst. If we can 
all agree that the process is vulnerable, then it seems that we'd have a strong 
argument for banning it.

- Wayne

[1]
https://wiki.mozilla.org/CA/Forbidden_or_Problematic_Practices#Delegation_of_Domain_.2F_Email_Validation_to_Third_Parties


On Thu, May 23, 2019 at 12:22 PM Kathleen Wilson via dev-security-policy < 
dev-security-policy@lists.mozilla.org> wrote:

> On 5/13/19 10:24 AM, Wayne Thayer wrote:
> > The BRs forbid delegation of domain and IP address validation to 
> > third parties. However, the BRs don't forbid delegation of email 
> > address validation nor do they apply to S/MIME certificates.
> >
> > Delegation of email address validation is already addressed by 
> > Mozilla's Forbidden Practices [1] state:
> >
> > "Domain and Email validation are core requirements of the Mozilla's 
> > Root Store Policy and should always be incorporated into the issuing 
> > CA's procedures. Delegating this function to 3rd parties is not permitted."
> >
> > I propose that we move this statement (changing "the Mozilla's Root 
> > Store Policy" to "this policy") into policy section 2.2 "Validation 
> > Practices".
> >
> > This is https://github.com/mozilla/pkipolicy/issues/175
> >
> > I will appreciate everyone's input on this proposal.
> >
> > - Wayne
> >
> > [1]
> >
> https://wiki.mozilla.org/CA/Forbidden_or_Problematic_Practices#Delegat
> ion_of_Domain_.2F_Email_Validation_to_Third_Parties
> >
>
>
> All,
>
> As the person who filed the Github issue for this, I would like to 
> provide some background and my opinion.
>
> Currently the 'Delegation of Domain / Email Validation to Third Parties'
> section of the 'Forbidden Practices' page says:
> "This is forbidden by the Baseline Requirements, section 1.3.2.
> Domain and Email validation are core requirements of the Mozilla's 
> Root Store Policy and should always be incorporated into the issuing 
> CA's procedures. Delegating this function to 3rd parties is not permitted."
>
> Based on the way that section is written, it appears that domain 
> validation (and the BRs) was the primary consideration, and that the 
> Email part of it was an afterthought, or added later. Historically, my 
> attention has been focused on TLS certs, so it is possible that the 
> ramifications of adding Email validation to this section was not fully 
> thought through.
>
> I don't remember who added this email validation text or when, but I 
> can tell you that when I review root inclusion requests I have only 
> been concerned about making sure that domain validation is not being 
> delegated to 3rd parties. It wasn't until a representative of a CA 
> brought this to my attention that I realized that there has been a 
> difference in text on this wiki page versus the rules I have been 
> trying to enforce. That is when I filed the github issue.
>
> I propose that we can resolve this discrepancy for now by removing "/ 
> Email Validation" from the title of the section and removing "and Email"
> from the contents of the section.
>
> Unless we believe there are significant security reasons to add our 
> own S/MIME required/forbidden practices at this time, my preference is 
> to wait for the CA/Browser Forum to create the S/MIME Working Group, 
> and for that group to identify the S/MIME baseline requirements. Then 
> we can add policy and required/forbidden practices based on the S/MIME 
> BRs provided by that group.
>
> I do realize that my proposal is unfair to CAs who have been 
> diligently following this section of this wiki page. Your diligence is 
> appreciated, and your contributions to this discussion will also be 
> appreciated.
>
> Thanks,
> Kathleen
>
>
>
>
>
>
>
>
>
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>
>
> _______________________________________________
> dev-security-policy mailing list
> dev-security-policy@lists.mozilla.org
> https://lists.mozilla.org/listinfo/dev-security-policy
>
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