[Servercert-wg] Discussion Period Begins - Ballot SC-080 V1: "Sunsetting use of WHOIS to identify Domain Contacts"

Mon Sep 23 19:47:57 UTC 2024

[Responding to the most recent message in the discussion, apologies if this
causes unexpected threading.]

Hi all,

Given the discussion thus far, I’d like to propose the following for the
group’s consideration in an effort to help guide a second round of
discussion (TBD, but expected to begin no earlier than September 30).

*Objective 1: Enhance WHOIS/RDAP validation of gTLDs with comparable
security properties to DNS-based validation and sunset WHOIS/RDAP for
ccTLDs.*

*Justification: *

   - A recent disclosure [1] demonstrated how threat actors could exploit
   deficiencies in the WHOIS protocol and WHOIS tools served via HTTPS
   websites to obtain fraudulent TLS certificates.
   - Discussions within the Mozilla Dev Security Policy (MDSP) community
   [2] further expressed corresponding risks related to WHOIS, while also
   noting that ccTLDs may not maintain accurate or up-to-date WHOIS server
   records. Several examples of inoperative WHOIS servers for ccTLDs were
   identified.
   - Discussion in [3] further called into question the reliability of
   ccTLD WHOIS servers given, per IANA, there is no global policy requirement
   for ccTLD managers to operate a WHOIS server, and if they do, what kind of
   information is provided.
   - Solutions to strengthen existing WHOIS lookup methods were proposed in
   [4] and are considered in this update.

*Approach: *

   - Add the following requirements in Sections 3.2.2.4.2 (“Email, Fax,
   SMS, or Postal Mail to Domain Contact”), 3.2.2.4.12 (“Validating Applicant
   as a Domain Contact”), and 3.2.2.4.15 (“Phone Contact with Domain Contact”).

“
*Effective January 15, 2025, when issuing Subscriber Certificates…*

   - *The CA MUST NOT rely on Domain Contact information obtained using an
   HTTPS website, regardless of whether previously obtained information is
   within the allowed reuse period.*
   - *The CA MUST NOT rely on Domain Contact information obtained using the
   WHOIS protocol (RFC 3912) or the Registry Data Access Protocol (RFC 7482)
   if the requested Domain Name contains a ccTLD, regardless of whether
   previously obtained information is within the allowed reuse period.*
   - *When obtaining Domain Contact information using the WHOIS protocol,
   the CA MUST query IANA's WHOIS server and follow referrals to the
   appropriate gTLD WHOIS server.*
   - *When obtaining Domain Contact information using the Registry Data
   Access Protocol, the CA MUST utilize IANA's bootstrap file to identify and
   query the correct RDAP server for the domain.*
   - *The CA SHOULD NOT rely on cached 1) WHOIS server information or 2)
   RDAP bootstrap data from IANA to ensure that it relies upon up-to-date and
   accurate information.*”

*Objective 2: Sunset Methods 3.2.2.4.2 (“Email, Fax, SMS, or Postal Mail to
Domain Contact”) and 3.2.2.4.15 (“Phone Contact with Domain Contact”).*
*Justification:*

   - While solutions to strengthen WHOIS-relying DCV methods are considered
   in this update (above), there is limited public evidence of significant
   reliance on these methods, including in response to [2] and [5].
   - Instead, discussion has identified at least one CA Owner has already
   sunset reliance on WHOIS [6], and another that has changed its approach [7]
   for relying on WHOIS since disclosure of [1].
   - More modern and heavily relied-upon DCV methods offer advantages over
   the existing WHOIS-based methods, including greater opportunity for
   seamless certificate lifecycle management automation (e.g., [8] and [9]),
   while also benefiting from recently improved security practices [10]. These
   methods can also more effectively align subscriber capabilities with
   agility and resilience expectations necessary to respond to the revocation
   timelines described in the TLS BRs [11].
   - Beyond the above, previous discussions within the CA/Browser Forum
   have raised concerns about the perceived value (e.g., [12]) and security
   (e.g., [13]) of the DCV methods relying on WHOIS, further supporting the
   rationale for their gradual sunset.

*Approach:*

   - Add the following requirements to Sections 3.2.2.4.2 (“Email, Fax,
   SMS, or Postal Mail to Domain Contact”) and 3.2.2.4.15 (“Phone Contact with
   Domain Contact”).

“*Effective September 15, 2025, the CA MUST NOT rely on this method.*”

The effective dates considered in this update are intended to 1) address
the immediate concerns identified by [1], 2) offer near-term and
longer-term transition periods for subscribers and CA Owners relying on
existing implementations of these methods, and 3) align with existing
effective dates in the TLS BRs (e.g., [10]).

The above proposed updates compared to the initial effort described in [14]
are highlighted at [15]. A comparison of these proposed updates against the
in-force BRs is available at [16]

Comments are welcome either on-list or with suggested edits via GitHub
(preferred) at [17].

Thanks,
Ryan

[1]
https://labs.watchtowr.com/we-spent-20-to-achieve-rce-and-accidentally-became-the-admins-of-mobi/
[2]
https://groups.google.com/a/mozilla.org/g/dev-security-policy/c/FuOi_uhQB6U/m/hKJOz3XzAAAJ
[3]
https://groups.google.com/a/mozilla.org/g/dev-security-policy/c/mAl9XjieSkA/m/oDNWxtPwAQAJ
[4]
https://archive.cabforum.org/pipermail/servercert-wg/2024-September/004839.html
[5]
https://archive.cabforum.org/pipermail/servercert-wg/2024-September/004844.html
[6]
https://aws.amazon.com/blogs/security/aws-certificate-manager-will-discontinue-whois-lookup-for-email-validated-certificates/
[7] https://bugzilla.mozilla.org/show_bug.cgi?id=1917896
[8]
https://cabforum.org/working-groups/server/baseline-requirements/requirements/#32247-dns-change
[9]
https://cabforum.org/working-groups/server/baseline-requirements/requirements/#322419-agreed-upon-change-to-website---acme
[10]
https://cabforum.org/working-groups/server/baseline-requirements/requirements/#3229-multi-perspective-issuance-corroboration
[11]
https://cabforum.org/working-groups/server/baseline-requirements/requirements/#491-circumstances-for-revocation
[12]
https://archive.cabforum.org/pipermail/servercert-wg/2018-August/000113.html
[13] https://lists.cabforum.org/pipermail/validation/2024-July/001995.html
[14]
https://archive.cabforum.org/pipermail/servercert-wg/2024-September/004825.html
[15]
https://github.com/ryancdickson/staging/compare/356799f0dcfe11deb0a375a11233403236ab72c9..7a2ea7b33611bebf006a99a9a82729f183143eac
[16]
https://github.com/ryancdickson/staging/compare/ba28d04894d69c8fac62850b9d0de5061658c7c5..7a2ea7b33611bebf006a99a9a82729f183143eac
[17] https://github.com/ryancdickson/staging/pull/9

On Wed, Sep 18, 2024 at 3:11 PM Amir Omidi via Servercert-wg <
servercert-wg at cabforum.org> wrote:

> I do not know much about the state of subdomain auth deployment in the CA
> ecosystem unfortunately.
>
> On Wed, Sep 18, 2024 at 2:09 PM Andrew Ayer <agwa at andrewayer.name> wrote:
>
>> Hi Amir,
>>
>> On Wed, 18 Sep 2024 15:48:38 +0000
>> Amir Omidi via Servercert-wg <servercert-wg at cabforum.org> wrote:
>>
>> > There are two CAs (Let's Encrypt and Google Trust Services) with
>> > DNS-ACCOUNT-01 (
>> > https://datatracker.ietf.org/doc/draft-ietf-acme-scoped-dns-challenges/
>> )
>> > mostly ready to go. This draft is designed to solve the CNAME
>> > delegation problem.
>>
>> It doesn't obviate the need to run an acme-dns server (or similar) but
>> DNS-ACCOUNT-01 would indeed be a great help.  Note that RFC9444
>> (subdomain auth) support is also needed as otherwise the subscriber
>> has to add delegations for every hostname instead of just one per zone.
>> Do you know what the state of CA adoption is there?
>>
>> In any case, I'll give this I-D a more thorough look and provide
>> feedback in the ACME WG.
>>
>> Regards,
>> Andrew
>>
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>
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