Thanks Jeremy.

On Thu, Oct 3, 2019 at 5:06 PM Jeremy Rowley <>

> Hey Wayne,
> I think there might be confusion on how the notification is supposed to
> happen. Is notification through CCADB sufficient? We've uploaded all of the
> Sub CAs to CCADB including the technically constrained ICAs. Each one that
> is hosted/operated by itself is marked that way using the Subordinate CA
> Owner field. Section 8 links to emailing but
> operationally, CCADB has become the default means of providing this notice.
> If you're expecting email, that may be worth clarifying in case CAs missed
> that an email is required. I know I missed that, and because CCADB is the
> common method of notification there is a chance that notice was considered
> sent but not in the expected way.
Considering that section 8 links to an email address where it states
"MUST notify
Mozilla <>", I'm skeptical that there is confusion,
but I do agree that it makes sense for the notification to be triggered via
an update to CCADB rather than an email. I'll look in to this.

There's also confusion over the "new to Mozilla" language I think. I
> interpreted this language as organizations issued cross-signs after the
> policy. For example, Siemens operated a Sub CA through Quovadis prior to
> policy date so they aren't "new" to the CA space even if they were
> re-certified.

That's the correct interpretation, barring any further clarifications...

However, they would be new in the sense you identified - they haven't gone
> through an extensive review by the community.  If the goal is to ensure the
> community review happens for each Sub CA, then requiring all
> recertifications to go through an approval process makes sense instead of
> making an exception for new. I'm not sure how many exist currently, but if
> there are not that many organizations, does a grandfathering clause cause
> unnecessary complexity? I realize this is not in DigiCert's best interest,
> but the community may benefit the most by simply requiring a review of all
> Sub CAs instead of trying to grandfather in existing cross-signs.  Do you
> have an idea on the number that might entail? At worst, we waste a bunch of
> time discovering that all of these are perfectly operated and that they
> could have been grandfathered in the first place. At best, we identify some
> critical issues and resolve them as a community.
It appears to be at least 2 dozen organizations, based on the "subordinate
CA owner" field in CCADB. I say "at least" because, as Dimitris noted,
we're just now identifying intermediates that are incorrectly labeled as
falling under the parent certificate's audits.

If there are a significant number of unconstrained on-prem CAs, then
> language that requires a review on re-signing would be helpful.  Perhaps
> say "As of X date, a CA MUST NOT sign a non-technically constrained
> certificate where cA=True for keys that are hosted external to the CA's
> infrastructure or that are not operated in accordance with the issuing CA's
> policies and procedures unless Mozilla has first granted permission for
> such certificate"? The wording needs work of course, but the idea is that
> they go through the discussion and Mozilla signs off. A process for
> unconstrained Sub CAs that is substantially similar to the root inclusion
> makes sense, but there is documentation on CCADB for the existing ones.
> Still, this documentation should probably made available, along with the
> previous incident reports, to the community for review and discussion.
> Afterall, anything not fully constrained is essentially operating the same
> as a fully embedded root.
Grandfathering in organizations currently in control of an unconstrained
subordinate CA, but requiring them to go through an approval process before
obtaining a new subordinate CA certificate seems like a good approach. I do
however have concerns about requiring a process similar to the root
inclusion process. We expect the root CA to take responsibility for the
organizations they certify, so a lighter process that acts as a
verification of the decision made by the root CA is appropriate here. To
put it another way, applying the full root inclusion process to externally
operated unconstrained subordinate CA certificates is not much different
than forbidding them. I do agree that policy docs and audits should be made
available as part of this review.

Speaking on a personal, non-DigiCert note, I think on-prem sub CAs are a
> bad idea, and I fully support more careful scrutiny on which entities are
> controlling keys. Looking at the DigiCert metrics, the on-prem Sub CAs are
> responsible for over half of the incident reports, with issues ranging from
> missed audit dates to incorrect profile information. The long cycle in
> getting information,  being a middle-man information gathering, and trying
> to convey both Mozilla and CAB forum policy makes controlling compliance
> very difficult, and a practice I would not recommend to any CA. Once you've
> established a relationship as a signer CA (or acquired a relationship),
> extraditing yourself is... difficult.  The certificates end up embedded on
> smart cards, used by government institutions and pinned in weird places.
> And the unfortunate part is you don't have the direct relationship with the
> end-user to offer counsel against some of the practices. That extra
> abstraction layer between the CA and root store program ends up adding a
> lot more complexity than you'd initially think. Delegating the CA
> responsibility ends up being a bad idea and takes years to fix. DigiCert is
> finally down to the final few TLS sub CAs (5) and each are operating in
> OCSP signing mode only. They'll all be revoked in 2020.
Unless I'm missing something, DigiCert is continuing to issue externally
operated S/MIME sub CAs, e.g.

> -----Original Message-----
> From: dev-security-policy <>
> On Behalf Of Wayne Thayer via dev-security-policy
> Sent: Thursday, October 3, 2019 2:45 PM
> To: mozilla-dev-security-policy <
> Subject: Re: Policy 2.7 Proposal:Extend Section 8 to Encompass Subordinate
> CAs
> I'd like to revisit this topic because I see it as a significant change
> and am surprised that it didn't generate any discussion.
> Taking a step back, a change [1] to notification requirements was made
> last year to require CAs that are signing unconstrained subordinate CAs
> (including cross-certs) controlled by a different organization to notify
> Mozilla. We have received few, if any, notifications of this nature, so I
> have to wonder if CAs are adhering to this requirement.
> This requirement applies as follows:
> an organization other than the CA obtains control of an unconstrained
> > intermediate certificate (as defined in section 5.3.2 of this policy)
> > that directly or transitively chains to the CA's included
> > certificate(s);
> >
> Is the "obtains control" language being interpreted to mean that this only
> applies when control of the private keys change, and not when a CA signs a
> key controlled by a different organization? I believe the intent is for
> this to apply in both situations - otherwise it is trivial to bypass.
> The new change [2] proposed for version 2.7 of our policy goes one step
> further and places transfers and signings of unconstrained subordinate CAs
> clearly in the scope of section 8.1, including the following language:
> If the receiving or acquiring company is new to the Mozilla root program,
> > it must demonstrate compliance with the entirety of this policy and
> > there MUST be a public discussion regarding their admittance to the
> > root program, which Mozilla must resolve with a positive conclusion in
> > order for the affected certificate(s) to remain in the root program.
> > If the entire CA operation is not included in the scope of the
> > transaction, issuance is not permitted until the discussion has been
> resolved with a positive conclusion.
> That means any organization "new to the Mozilla root program" for which a
> CA signs an unconstrained subordinate CA or cross-cert must go through an
> approval process including a public discussion before issuing certificates
> in order to comply with this policy.
> It also means that we need to decide what "new to the Mozilla root program"
> means. Organizations that control unconstrained subordinate CAs have not
> been considered members of the program in the past, so it's easy to argue
> that every such organization will be "new to the Mozilla root program"
> if/when this policy goes into effect. However, it may be more practical to
> "grandfather in" organizations that are currently in control of
> unconstrained subordinate CAs.
> This also raises the question of what it means to "demonstrate compliance
> with the entirety of this policy". Section 8.1 has historically applied to
> companies acquiring root CAs and we have not required them to go through
> the entire inclusion process - only a public discussion. Should that same
> interpretation apply to unconstrained subordinate CA?
> Before proposing any changes, I'd like to ask for everyone's input on
> these and any other concerns stemming from this policy proposal.
> - Wayne
> [1]
> [2]
> On Fri, May 10, 2019 at 1:58 PM Wayne Thayer <> wrote:
> > Having received no comments on these proposed changes, I plan to
> > include them in version 2.7 of our policy.
> >
> > - Wayne
> >
> > On Fri, Apr 19, 2019 at 11:55 AM Wayne Thayer <>
> wrote:
> >
> >> Ryan Sleevi made the following proposal:
> >>
> >> Issue #122 [1] previously discussed Section 8 in the context of
> >>> subordinate CAs, with a change [2] being made to include subordinate
> >>> CAs (in the context of Section 5.3.2) within scope of notification
> requirements.
> >>>
> >>> However, as presently worded, it's ambiguous as to whether or not
> >>> Sections 8.1 through 8.3 also apply to subordinate CAs, or whether
> >>> the only disclosure required is upon the initial introduction of the
> subordinate.
> >>> This confusion results from language such as in Section 8.1, "or
> >>> when an organization buys the private key of a certificate in
> >>> Mozilla's root program", implying that private keys which
> >>> transitively chain to a root certificate within Mozilla's program are
> exempt from such requirements.
> >>>
> >>> This ambiguity creates incentives for situations such as
> >>> cross-signing CAs that might otherwise or have been otherwise
> >>> rejected from direct inclusion within the Mozilla program. It
> >>> further creates issues with respect to the supervision of audits and
> auditors.
> >>>
> >>> While it is true that the signing CA accepts the risk that an
> >>> unfavorable verdict on the subordinate may impact the root, the cost
> >>> of such a decision is primarily borne by Mozilla and the broader
> >>> community, in that they are responsible for the collateral ecosystem
> >>> challenges and devising appropriate solutions. This has been
> >>> demonstrated, for example, through the discussion of Symantec issues
> [3].
> >>>
> >>> Because Mozilla and the community bear significant cost, especially
> >>> as more time passes and more certificates are issued, the following
> >>> changes are suggested:
> >>>
> >>>    1. Align Section 8, and its subsections, with language similar to
> >>>    that of Section That is, that the policy is applicable to
> a CA and
> >>>    all subordinate CAs technically capable of issuing (server or
> e-mail)
> >>>    certificates
> >>>    2. With respect to Section 8.1, extend the requirements of the last
> >>>    paragraph to the issuance of subordinate CA certificates. Namely,
> if the
> >>>    private key is in possession of an entity that is new to the
> Mozilla root
> >>>    program, or subject to a CP or CPS that is new to the Mozilla Root
> Program,
> >>>    that prior to the issuance of such a certificate, there be a public
> >>>    discussion that results in a favorable conclusion.
> >>>
> >>> With the current policy as written, an existing/included root CA
> >>> that plans to exit the CA business might be prohibited (by virtue of
> >>> Section
> >>> 8.1) from selling the business or (by virtue of Section 8.3) from
> >>> transferring the private key material. However, they are fully
> >>> permitted to cross-certify a new 'root' and then proverbially close
> >>> up shop - with no consideration for if their root gets removed as a
> >>> consequence. These are the same set of concerns that led to the
> >>> introduction of Section 8, but today exist due to the ambiguity with
> respect to the subsections.
> >>>
> >>
> >> I've proposed a fix for this issue:
> >>
> >> 1a5639e70f1f0a8 It also attempts to clarify the applicability of
> >> section 8.3 as "only"
> >> when section 8.1 and/or section 8.2 also apply.
> >>
> >> This is and
> >>
> >>
> >> I will greatly appreciate everyone's input on this topic. In
> >> particular, I would like to hear from CAs that would be affected by
> >> the requirement for any new subordinate CAs to go through a public
> >> discussion before issuing certificates, with the outcome being
> >> positive or else the subordinate CA certificate will be added to OneCRL
> (section 8.1).
> >>
> >> - Wayne
> >>
> >> [1]
> >> [2]
> >>
> >> 1a11f860c30dc10 [3]
> >>
> >
> _______________________________________________
> dev-security-policy mailing list
dev-security-policy mailing list

Reply via email to