On Sunday, January 3, 2021 at 8:38:05 AM UTC-6, Jeff Ward wrote:
> On Tuesday, December 15, 2020 at 2:41:10 PM UTC-6, Ben Wilson wrote: 
> > All, 
> > 
> > This email is part of the discussion for the next version of the Mozilla 
> > Root Store Policy (MSRP), version 2.7.1, to be published during of Q1-2021. 
> > 
> > For audit delays, we currently require that audit statements disclose the 
> > locations that were and were not audited, but that requirement has not been 
> > incorporated yet into the MRSP. See 
> > https://wiki.mozilla.org/CA/Audit_Statements#Minimum_Expectations. That 
> > provision reads as follows: 
> > 
> > Disclose each location (at the state/province level) that was included in 
> > the scope of the audit or should have been included in the scope of the 
> > audit, whether the inspection was physically carried out in person at each 
> > location, and which audit criteria were checked (or not checked) at each 
> > location. 
> > 
> > - If the CA has more than one location in the same state/province, then 
> > use terminology to clarify the number of facilities in that state/province 
> > and whether or not all of them were audited. For example: "Facility 1 in 
> > Province", "Facility 2 in Province, Facility 3 in Province" *or* 
> > "Primary Facility in Province", "Secondary Facility in Province", "Tertiary 
> > Facility in Province". 
> > - The public audit statement does not need to identify the type of 
> > Facility. 
> > - "Facility" includes: data center locations, registration authority 
> > locations, where IT and business process controls of CA operations are 
> > performed, facility hosting an active HSM with CA private keys, 
> > facility or 
> > bank deposit box storing a deactivated and encrypted copy of a 
> > private key. 
> > 
> > It is proposed by Issue #207 
> > <https://github.com/mozilla/pkipolicy/issues/207> that this language 
> > requiring the disclosure of site locations--audited and unaudited--be made 
> > clearly part of the MSRP by reference to the language above. 
> > 
> > A similar method of incorporating by reference has been taken in section 
> > 2.4 of the MSRP 
> > <https://www.mozilla.org/en-US/about/governance/policies/security-group/certs/policy/#24-incidents>
> >  
> > with respect to incident reporting and in section 7.1 
> > <https://www.mozilla.org/en-US/about/governance/policies/security-group/certs/policy/#71-inclusions>
> >  
> > with requirements for the CA inclusion process. 
> > 
> > It is proposed that we add a new subsection 10 to MRSP section 3.1.4 
> > <https://www.mozilla.org/en-US/about/governance/policies/security-group/certs/policy/#314-public-audit-information>
> >  
> > that would require that audit documentation disclose the facility site 
> > locations that were, or were not, examined. 
> > 
> > One concern that has been raised previously is that the Baseline 
> > Requirements do not define "facility site location". However, we believe 
> > that the language above at 
> > https://wiki.mozilla.org/CA/Audit_Statements#Minimum_Expectations 
> > accomplishes that. We're open to suggestions for re-wording parts of it to 
> > make it even better. 
> > 
> > Currently, the audit letter template for WebTrust for CAs references the 
> > site location audited (at the level of specificity that is proposed 
> > above). Over this past year, due to COVID, some ETSI attestation letters 
> > have also explained which sites were and were not checked. This approach 
> > seems to work, and the additional information will be beneficial in the 
> > future as we evaluate the security and trust of PKI service providers. 
> > 
> > So, for the page cited above, we intend to move "Minimum Expectations" out 
> > from under "Audit Delay" so that it stands separately as a requirement for 
> > disclosing the facility site location. Then we will also revise MRSP 
> > section 3.1.4 by inserting a new subsection 10 to require "facility site 
> > locations that were, or were not, examined" with a hyperlink to the Minimum 
> > Expectations language cited above. 
> > 
> > We look forward to your comments and suggestions. 
> > 
> > Sincerely yours, 
> > 
> > Ben
> Hi Ben. Happy New Year. I have asked the WebTrust Task Force members to 
> provide their comments and Don and I will then provide a more detailed 
> response. I wanted to be sure to get each of the major firms' feedback before 
> responding. 
> 
> Thank you. 
> 
> Jeff

Ben, Don and I offer the following response, which has been vetted through the 
WebTrust Task Force:

Proposed Requirement
Disclose each location (at the state/province level) that was included in the 
scope of the audit or should have been included in the scope of the audit, 
whether the inspection was physically carried out in person at each location, 
and which audit criteria were checked (or not checked) at each location.
•       If the CA has more than one location in the same state/province, then 
use terminology to clarify the number of facilities in that state/province and 
whether or not all of them were audited. For example: "Facility 1 in Province", 
"Facility 2 in Province, Facility 3 in Province" *or*"Primary Facility in 
Province", "Secondary Facility in Province", "Tertiary Facility in Province".
     
•       The public audit statement does not need to identify the type of 
Facility.
     
•       "Facility" includes: data center locations, registration authority 
locations, where IT and business process controls of CA operations are 
performed, facility hosting an active HSM with CA private keys, facility or 
bank deposit box storing a deactivated and encrypted copy of a private key.

Task Force Comments on Proposed Requirement
1.      Disclosure of each location that was included in the audit.   At the 
present time, both the public WebTrust report, as well as the detailed controls 
report, require disclosure of each location involved in the audit.  The 
specificity of disclosure can vary, often at the city level or higher, in order 
to protect the confidentiality of locations required by some CAs.

2.      Disclosure of whether the inspection was physically carried out in 
person at each location. This is not currently provided in the public WebTrust 
report nor would it likely be included in the future.   This detail, however, 
would likely be provided in a detailed controls report.

Mozilla is aware of the current WebTrust Covid-19 report scenarios where the 
auditor provides specific qualifications due to inability to physically attend 
a significant location due to COVID-19 lockdowns.   It is preferable to test 
controls in person at the organization’s location, however that is not a 
realistic expectation for the foreseeable COVID-19 future.  

It should also be noted that, in the scenario where multiple locations exist, 
an auditor may use sampling to test a sample of the locations where the 
controls exercised are common throughout the relevant hierarchy under audit 
(this is common in financial statement audits involving multiple locations). In 
this scenario some locations are physically audited and the remainder are 
tested through alternative means.

It should be noted that auditors are able to perform many testing procedures 
remotely/virtually with the same level of effectiveness as onsite/in-person. 
For example, auditors have been able to develop alternate procedures by 
combining virtual tours, log reviews, security camera footage and other testing 
methods to gain evidence supporting the operating effectiveness of controls 
without physically visiting a location. Testing physical security, 
environmental controls, offline ceremonies, and asset management are the 
exception and typically more effectively tested in-person. If the auditor is 
not able to obtain sufficient appropriate audit evidence to support a clean 
audit opinion a qualification and reasons therefore will continue to be set out 
in the WebTrust report.


3.      Definition of Facilities. The term “facility” is not defined in the 
CA/B Forum guidance (BRs) or formally in any other WebTrust materials. The 
functional term used in WebTrust (3.1, and 3.4) and in the BRs (5.4.1) is “CA 
facility”. CA facility is often understood to be a facility securing CA private 
keys within HSMs. Many CAs adopt this understanding in their respective CP and 
CPSs. This is an important distinction because section 5.1 of the BRs does not 
provide any requirements for physical security or environmental requirements. 
It also does not distinguish between the controls based on the types of 
facilities.  CAs detail the controls requirements of CA facilities but remain 
silent on controls at “registration authority locations” or “locations where IT 
and business process controls are performed.” Without consistently defined 
requirements for locations beyond CA facilities, there is potential for a wide 
variety of interpretation resulting in inconsistencies. 

With many employees working from home due to COVID-19, for example, performing 
registration authority activities for the CA, 
•       their homes could be declared to be a facility under the proposed 
definition, 
•       It would not make sense to declare such, include the location in an 
audit report, nor 
•       expect an auditor to physically visit such (which under COVID-19 
lockdown in most cases is illegal).

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