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Google have made a final decision on the various dates they plan to
implement as part of the consensus plan in the Symantec matter. The
message from blink-dev is included below.

Most of the dates have consensus - the dates for Symantec to implement
the Managed CA infrastructure are agreed by all, and the date for final
distrust of the old Symantec PKI is agreed by Google and Mozilla (to
within a week, at any rate). I proposed November 1st 2018. Google has
gone for October 23rd 2018; in practical terms, we would implement that
using Firefox 63 (October 16th) or 64 (November 27th).

However, there is some difference in the proposals for the date on which
browsers should dis-trust Symantec certificates issued before June 1st,
2016. This date is significant because after that, Symantec have been
required to log all their certs to CT and so there is much better
transparency of issuance practice. I proposed December 1st 2017. Google
strongly considered late January, but have finally chosen April 17th 2018.

We now have two choices. We can accept the Google date for ourselves, or
we can decide to implement something earlier. Implementing something
earlier would involve us leading on compatibility risk, and so would
need to get wider sign-off from within Mozilla, but nevertheless I would
like to get the opinions of the m.d.s.p community.

I would like to make a decision on this matter on or before July 31st,
as Symantec have asked for dates to be nailed down by then in order for
them to be on track with their Managed CA implementation timetable. If
no alternative decision is taken and communicated here and to Symantec,
the default will be that we will accept Google's final proposal as a
consensus date.

Gerv

-------- Forwarded Message --------
Subject: Re: [blink-dev] Intent to Deprecate and Remove: Trust in
existing Symantec-issued Certificates
Date: Thu, 27 Jul 2017 17:16:06 -0700
From: Darin Fisher <[email protected]>
To: Darin Fisher <[email protected]>
CC: blink-dev <[email protected]>

Representing Google Chrome and the Chromium open source project, what
follows is our final proposal on this matter.


We’d like to first thank the blink-dev community for your input on this
discussion. After taking this input into consideration along with the
latest responses from Symantec and Mozilla, we have produced the
following proposal that is intended to be our final plan of action on
this matter.


Chrome 66 will distrust Symantec-issued TLS certificates issued before
June 1, 2016:

Chrome 66 will distrust Symantec-issued TLS certificates issued before
June 1, 2016, which is tentatively scheduled to hit Canary on January
19, 2018; Beta on March 15, 2018; and Stable (the vast majority of
Chrome users) on April 17, 2018. Affected site operators are strongly
encouraged to replace their TLS certificates before March 15, 2018 to
prevent breakage. Although this is significantly later than our initial
proposal of August 2017 and Mozilla’s proposal for late 2017
<https://groups.google.com/d/msg/mozilla.dev.security.policy/gn1i2JNVCnc/y7IRQALJBgAJ>,
we think it hits an appropriate balance between the security risk to
Chrome users and minimizing disruption to the ecosystem. This time will
allow clear messaging and scheduling for site operators to update
certificates.


We considered a number of alternative dates for distrusting this subset
of existing certificates before landing on Chrome 66. Given the scale of
Symantec’s existing PKI and the impact to the ecosystem that these
mitigations pose, one of our goals was to consider dates that gave site
operators enough lead time, as well as to try to clear end-of-year time
periods where production freezes are typically in place. Chrome 62 which
comes out in October 2017 was seriously considered, but was rejected due
to concerns around not giving enough lead time for site operators.
Chrome 63 which comes out in December was rejected due to overlapping
with end-of-year freezes. Chrome 64 which comes out in late January 2018
was strongly considered, but its early release channels also overlap
with holiday and end of year freezes. Chrome 65’s branch point is close
to the new year, and could present a challenge for some site operators.
Hence, Chrome 66 was chosen as the final approach.


Site operators currently using Symantec-issued TLS server certificates
that were issued before June 1, 2016 need to replace these certificates
as soon as possible to avoid disruption to their users. The distrust of
these certificates is necessary and is specifically targeted at removing
the risk of trusting old certificates that were issued under an
inadequately controlled infrastructure. Site operators can choose to
obtain their certificates from any trusted Certificate Authority.
Although the old infrastructure will be distrusted in the future (see
below), site operators with critical dependencies on Symantec’s current
infrastructure may also obtain replacement certificates from Symantec,
provided these certificates comply with the existing Chrome requirements
<https://security.googleblog.com/2015/10/sustaining-digital-certificate-security.html>for
new certificates issued from Symantec.


While we intend to stick with this schedule, if there is new information
highlighting additional security risks with this set of certificates,
the dates could change to more rapidly distrust the existing certificates.


Chrome 70 will distrust TLS certificates issued from Symantec’s old
infrastructure:

In order to complete this migration, we will be removing trust in all
certificates issued by Symantec’s old infrastructure in Chrome 70. This
includes any replacement certificates issued by Symantec prior to the
transition to the non-Symantec-operated “Managed Partner Infrastructure
<https://docs.google.com/document/d/1Yd079EsKQ-QawTvWgjIfrCV6d0NNlwoS1ftB0MaJkBc/>”.
Chrome 70 is tentatively scheduled to first reach Beta on September 13,
2018 and Stable on October 23, 2018, which is approximately 5 months
after Chrome 66’s corresponding dates.


By these dates, affected site operators will need to have fully replaced
any TLS server certificates issued from Symantec’s old infrastructure,
using any trusted CA including the new Managed Partner Infrastructure.
Failure to migrate a site to one of these two options will result in
breakage when Chrome 70 is released.


Reference Timeline:

In order to distill Chrome’s final plan into an actionable set of
information for site operators, we’ve drawn up a timeline of relevant
dates associated with this plan. As always, Chrome release dates can
vary by a number of days, but upcoming release dates can be tracked here
<https://www.chromium.org/developers/calendar>.


Date

Event

July 27, 2017

through

~March 15, 2018

Site Operators using Symantec-issued TLS server certificates issued
before June 1, 2016 should replace these certificates. These
certificates can be replaced by any currently trusted CA, including
Symantec.

~October 24, 2017

Chrome 62 released to Stable, which will add alerting in DevTools when
evaluating certificates that will be affected by the Chrome 66 distrust.

December 1, 2017

According to Symantec, the new Managed Partner Infrastructure will at
this point be capable of full issuance. Any certificates issued by
Symantec’s old infrastructure after this point will cease working in a
future Chrome update.


>From this date forward, Site Operators can obtain TLS server
certificates from the new Managed Partner Infrastructure that will
continue to be trusted after Chrome 70 (~October 23, 2018).


December 1, 2017 does not mandate any certificate changes, but
represents an opportunity for site operators to obtain TLS server
certificates that will not be affected by Chrome 70’s distrust of the
old infrastructure.

~March 15, 2018

Chrome 66 released to beta, which will remove trust in Symantec-issued
certificates with a not-before date before June 1, 2016. As of this
date, in order to ensure continuity of operations, Site Operators must
be using either a Symantec-issued TLS server certificate issued on or
after June 1, 2016 or a currently valid certificate issued from any
other trusted CA as of Chrome 66.


Site Operators that obtained a certificate from Symantec’s old
infrastructure after June 1, 2016 are unaffected by Chrome 66 but will
need to obtain a new certificate by the Chrome 70 dates described below.

~April 17, 2018

Chrome 66 released to Stable.

~September 13, 2018

Chrome 70 released to Beta, which will remove trust in the old
Symantec-rooted Infrastructure. This will not affect any certificate
chaining to the new Managed Partner Infrastructure, which Symantec has
said will be operational by December 1, 2017.


Only TLS server certificates issued by Symantec’s old infrastructure
will be affected by this distrust regardless of issuance date.

~October 23, 2018

Chrome 70 released to Stable.

A note on the Blink process and this Intent:

As mentioned at the start of this discussion, the Google Chrome team
<https://groups.google.com/a/chromium.org/d/msg/blink-dev/eUAKwjihhBs/rpxMXjZHCQAJ>decided
to use the Blink Process <http://www.chromium.org/blink#new-features>in
discussing this change, as a way to gather feedback from site operators,
the Chromium community, other browsers, and the broader ecosystem about
how to balance the interoperability risk and compatibility risk. A goal
of this process is to balance risk by aligning on interoperable
solutions, minimize ambiguity, and provide transparency into the
decision making process. This process was designed around balancing
changes to the Web Platform APIs, and we recognize there are further
opportunities to improve this for Certificate Authority decisions. As
those improvements are not yet in place, we will be forgoing the Blink
API owner LGTM process for approval, and treating this more as a
product-level decision instead.


Thanks to everyone who put in so much time and energy to arrive at this
point.


On Sun, May 7, 2017 at 4:57 PM, Darin Fisher <[email protected]
<mailto:[email protected]>> wrote:

I wanted to give folks an update about the current state of this
Intent. Given all of the feedback we've received from the community,
right now we are continuing to evaluate different options and are
improving our understanding of the impact these proposals would have
on the ecosystem. We understand the desire to reach closure here,
but also want to make sure that we take the appropriate amount of
time to ensure that we come up with the best possible proposal. If
you have additional feedback that could help inform our decision, we
welcome hearing it.

Thanks,
-Darin

On Thu, Mar 23, 2017 at 9:02 AM, Ryan Sleevi <[email protected]
<mailto:[email protected]>> wrote:

Note: Historically, the Google Chrome team has not used the
Blink Process <http://www.chromium.org/blink#new-features>for
Certificate Authority-related security issues, of which there
have been a number over the years. However, we are interested in
exploring using this process for such changes, as it provides a
greater degree of transparency and public participation. Based
on the level of participation and feedback we receive, we may
consider using this for the future. However, as CA-related
security incidents may require immediate response to protect
users, this should not be seen as a guarantee that this process
can be used in future incident responses.


Primary eng (and PM) emails:

[email protected]
<mailto:[email protected]>[email protected]
<mailto:[email protected]>


Summary

Since January 19, the Google Chrome team has been investigating
a series of failures by Symantec Corporation to properly
validate certificates. Over the course of this investigation,
the explanations provided by Symantec have revealed a
continually increasing scope of misissuance with each set of
questions from members of the Google Chrome team; an initial set
of reportedly 127 certificates has expanded to include at least
30,000 certificates, issued over a period spanning several
years. This is also coupled with a series of failures following
the previous set of misissued certificates from Symantec

<https://security.googleblog.com/2015/10/sustaining-digital-certificate-security.html>,
causing us to no longer have confidence in the certificate
issuance policies and practices of Symantec over the past
several years. To restore confidence and security of our users,
we propose the following steps:

*

A reduction in the accepted validity period of newly issued
Symantec-issued certificates to nine months or less, in
order to minimize any impact to Google Chrome users from any
further misissuances that may arise.

*

An incremental distrust, spanning a series of Google Chrome
releases, of all currently-trusted Symantec-issued
certificates, requiring they be revalidated and replaced.

*

Removal of recognition of the Extended Validation status of
Symantec issued certificates, until such a time as the
community can be assured in the policies and practices of
Symantec, but no sooner than one year.


Motivation

As captured in Chrome’s Root Certificate Policy
<https://www.chromium.org/Home/chromium-security/root-ca-policy>,
root certificate authorities are expected to perform a number of
critical functions commensurate with the trust granted to them.
This includes properly ensuring that domain control validation
is performed for server certificates, to audit logs frequently
for evidence of unauthorized issuance, and to protect their
infrastructure in order to minimize the ability for the issuance
of fraudulent certs.


On the basis of the details publicly provided by Symantec, we do
not believe that they have properly upheld these principles, and
as such, have created significant risk for Google Chrome users.
Symantec allowed at least four parties access to their
infrastructure in a way to cause certificate issuance, did not
sufficiently oversee these capabilities as required and
expected, and when presented with evidence of these
organizations’ failure to abide to the appropriate standard of
care, failed to disclose such information in a timely manner or
to identify the significance of the issues reported to them.


These issues, and the corresponding failure of appropriate
oversight, spanned a period of several years, and were trivially
identifiable from the information publicly available or that
Symantec shared.


The full disclosure of these issues has taken more than a month.
Symantec has failed to provide timely updates to the community
regarding these issues. Despite having knowledge of these
issues, Symantec has repeatedly failed to proactively disclose
them. Further, even after issues have become public, Symantec
failed to provide the information that the community required to
assess the significance of these issues until they had been
specifically questioned. The proposed remediation steps offered
by Symantec have involved relying on known-problematic
information or using practices insufficient to provide the level
of assurance required under the Baseline Requirements and
expected by the Chrome Root CA Policy.


In January 2015, Symantec-issued certificates represented more
than 30% of the valid certificates by volume. While changes in
the CA ecosystem have seen that share decrease over the past two
years, there is still a significant compatibility risk for an
immediate and complete distrust. Further, due to overall TLS
ecosystem concerns, we understand that it may take non-trivial
effort for some site operators to find suitable solutions, as
the need to support older devices may necessitate the use of
particular CAs, meaning that distrust of new certificates also
has significant compatibility risk.


To balance the compatibility risks versus the security risks, we
propose a gradual distrust of all existing Symantec-issued
certificates, requiring that they be replaced over time with
new, fully revalidated certificates, compliant with the current
Baseline Requirements. This will be accomplished by gradually
decreasing the ‘maximum age’ of Symantec-issued certificates
over a series of releases, distrusting certificates whose
validity period (the difference of notBefore to notAfter)
exceeds the specified maximum.


The proposed schedule is as follows:

Chrome 59 (Dev, Beta, Stable): 33 months validity (1023 days)

Chrome 60 (Dev, Beta, Stable): 27 months validity (837 days)

Chrome 61 (Dev, Beta, Stable): 21 months validity (651 days)

Chrome 62 (Dev, Beta, Stable): 15 months validity (465 days)

Chrome 63 (Dev, Beta): 9 months validity (279 days)

Chrome 63 (Stable): 15 months validity (465 days)

Chrome 64 (Dev, Beta, Stable): 9 months validity (279 days)


The proposed schedule attempts to avoid making changes in Chrome
63 Stable, as that would be released during the winter holiday
production freeze many organizations undergo. This is solely to
reduce disruption for site operators and users, and attempts to
resume with Chrome 64 following the holiday season. Further, the
practical impact of the changes in Chrome 59 and 60 are
relatively minimal, due to many of the certificates issued
during that period of time being issued using SHA-1, which is no
longer supported for certificates in Chrome.


In addition, we propose to require that all newly-issued
certificates must have validity periods of no greater than 9
months (279 days) in order to be trusted in Google Chrome,
effective Chrome 61. This ensures that the risk of any further
misissuance is, at most, limited to nine months, and more
importantly, that if any further action is warranted or
necessary, that the entire ecosystem can migrate within that
time period, thus minimizing the risk of further compatibility
issues.


By combining these two steps, we can ensure that the level of
assurance in Symantec-issued certificates is able to match what
is expected by Google Chrome and the ecosystem, and that the
risks posed both from past and possible future misissuance is
minimized as much as possible.


Given the nature of these issues, and the multiple failures of
Symantec to ensure that the level of assurance provided by their
certificates meets the requirements of the Baseline Requirements
or Extended Validation Guidelines, we no longer have the
confidence necessary in order to grant Symantec-issued
certificates the “Extended Validation” status. As documented
with both the current and past misissuance, Symantec failed to
ensure that the organizational attributes, displayed within the
address bar for such certificates, meet the level of quality and
validation required for such display. Therefore, we propose to
remove such indicators, effective immediately, until Symantec is
able to demonstrate the level of sustained compliance necessary
to grant such trust, which will be a period no less than a year.
After such time has passed, we will consider requests from
Symantec to re-evaluate this position, in collaboration with the
broader Chromium community.


Compatibility and Interoperability Risk

As with any reduction in trust in a Certificate Authority, this
poses a non-trivial degree of compatibility risk. This is
because site operators desire to have their certificates
recognized in all client browsers, and if one or more browsers
fail to trust a given CA, this is prevented from happening.


On the other hand, all site operators expect that certificates
will only be issued for their domains upon their request, and
the failure to have that assurance significantly undermines the
security of HTTPS for both site operators and users.


This compatibility risk is especially high for Symantec-issued
certificates, due to their acquisition of some of the first CAs,
such as Thawte, Verisign, and Equifax, which are some of the
most widely supported CAs. Distrusting such CAs creates further
difficulty for providing secure connections to both old and new
devices alike, due to the need to ensure the CA a site operator
uses is recognized across these devices.


Further, the immediate distrust of a CA, as has been necessary
in the past, can significantly impact both site operators and
users. Site operators are forced to acquire certificates from
other CAs, without having the opportunity and time to research
which CAs best meet their needs, and users encounter a
substantial number of errors until those site operators act,
conditioning them to ignore security warnings. In the event that
only a single browser distrusts such a CA, the error is often
seen as the browser’s fault, despite it being a failure of the
CA to provide the necessary level of assurance, and the site
operator to respond in a timely fashion.


Assessing the compatibility risk with both Edge and Safari is
difficult, because neither Microsoft nor Apple communicate
publicly about their changes in trust prior to enacting them.


While Mozilla conducts their discussions regarding Certificate
Authorities in public, and were the first to be alerted of these
latest issues, they have not yet begun discussion of the next
steps to how best to protect their users. Our hope is that this
proposal may be seen as one that appropriately balances the
security and compatibility risks with the needs of site
operators, browsers, and users, and we welcome all feedback.


Alternative implementation suggestion for web developers

This proposal allows for web developers to continue to use
Symantec issued certificates, but will see their validity period
reduced. This ensure that web developers are aware of the risk
and potential of future distrust of Symantec-issued
certificates, should additional misissuance events occur, while
also allowing them the flexibility to continue using such
certificates should it be necessary.


Usage information from UseCounter

<https://code.google.com/p/chromium/codesearch#chromium/src/third_party/WebKit/Source/core/page/UseCounter.h&sq=package:chromium&type=cs&q=file:UseCounter.h%20Feature&l=39>:

For a variety of non-technical reasons, we do not currently
instrument the usage of CAs. Further, few public metrics exist
for intersecting usage information with the validity period,
since only certificates valid greater than nine months will be
affected outside of their normal replacement cycle. From Mozilla
Firefox’s Telemetry, we know that Symantec issued certificates
are responsible for 42% of certificate validations. However,
this number is not strictly an indicator for impact, as this
number is biased towards counting certificates for
heavily-trafficked sites, and whose issuance is fully automated
and/or whose validity periods will be unaffected, thus
significantly overstating impact. By phasing such changes in
over a series of releases, we aim to minimize the impact any
given release poses, while still continually making progress
towards restoring the necessary level of security to ensure
Symantec issued certificates are as trustworthy as certificates
from other CAs.

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