Thanks Jeff,

This is incredibly helpful to understand the approach (and limitations)
that are relevant in the context of a WebTrust report. I'm hoping our ETSI
colleagues might provide a similar level of detail, as I suspect this is
hardly "just" a WebTrust problem at this point.

On Fri, Mar 6, 2020 at 11:51 AM jwardcpa--- via dev-security-policy <
dev-security-policy@lists.mozilla.org> wrote:

> If the potential threat of a scope limitation is primarily due do an
> auditor not being able to travel to perform necessary testing, as with the
> Coronavirus, there are potential remedies for the auditor to consider,
> including, but not limited to:
>
> •       Using the work of another auditor, whereby the lead auditor
> verifies the independence, qualifications and technical competency of
> another firm that can do a portion of the work, and the lead auditor
> directs the work, plans, supervises and reviews the other auditor’s work,
> taking ultimate responsibility.  In this case, no mention of the other firm
> is made in the report as the lead auditor is taking responsibility for the
> other firm’s work.
> •       Using technology to observe physical controls and underlying
> documents/artifacts via remote means, such as video.  In this case, the
> auditor must ensure the authenticity, integrity, security and
> confidentiality of the transmission.
>

This is incredibly helpful to understand the possibilities! Thank you for
including this. While I can understand this might not be a universal
solution, especially as the virus continues to spread, it's incredibly
helpful to know what options might be possible and available.

If the auditor is able to design the audit plan in a manner that overcomes
> the challenges present from what otherwise would be a scope limitation, and
> can obtain satisfaction through adequate testing procedures, the auditor
> will be able to express an unqualified/unmodified (clean) opinion resulting
> in the ability to obtain the WebTrust seal.  Otherwise, the auditor will
> explain what gave rise to the scope limitation and no seal will be able to
> be issued.
> CAs should work with their auditors as early as possible to identify any
> impact on the scope of their audit and communicate any issues with the
> browsers.  It looks like from this thread any impact on the scope and the
> timing of the release of the audit should be documented in Bugzilla, which
> should also include the CAs incident response plan.
>

As a follow-up: would the use of such methods (a supervised auditor,
technology based controls) be something that would be available as part of
the Detailed Reporting? My understanding is that it would be noted in such
a report, but perhaps I'm assuming too much.


> So what happens if a modified opinion is provided by an auditor, for
> example, because a data center in China could not be tested in the normal
> course of the examination?  Then say, six months later, the data center
> becomes accessible and available for audit.  Since the audit for the year
> was already issued with the qualification, as required, you would have the
> option of waiting for the next annual audit to include the data center in
> question and proceed as normal.  Once again, a WebTrust audit cannot
> include a carve out of the data center, nor can a WebTrust audit be
> performed later on just the data center.  Depending on the significance of
> the operations not able to be included in the scope of the most current
> audit, and depending on the needs and requirements of the users (browsers),
> a CA could undergo specified/agreed-up procedures in a separate engagement,
> or conduct a full scope WebTrust audit when possible.  There ae no hard and
> fast rules for this situation and each should be treated on a case by case
> basis, with discussions including the CA, the browsers, and the auditor.
>

Thanks again for this. It's incredibly helpful to know the limitations here
as well, such as a limited-physical-scope audit being non-viable.

Are there limitations as to how long an audit in the past can be conducted?
That is, I'm imagining a scenario where a report is delivered, potentially
with the issues you note (qualified, adverse, disclaimer). Assuming there
comes a point in the future where the factors leading to that opinion are
eventually addressed, and access to the location again becomes possible, is
it possible to perform a full audit for the original period of time? That
is, for a CA that might have an audit period of March-to-March (and thus,
likely affected by these considerations), and the auditor is unable to
sufficiently determine to an unqualified opinion during that assessment
period (of March ~ June), is it possible to examine after-the-fact (e.g. if
the virus is contained by July, in July) for the original March-to-March
period? What challenges may exist for such audits that are further than 3
months from the audit period?

Realizing there's no hard and fast rules, I'm aware it's perhaps obvious
the line of thinking I'm going towards, which is to require provisions or
contracts for a full audit once/if the virus is contained and travel
restrictions are lifted, as part of accepting such a qualified or adverse
report. I'm also thinking of situations beyond the immediate incident, such
as natural disasters that may impact a region, and trying to understand if
there is an upper-bound or limit as to how far retroactively things may go.

In the situation of the Mar-Mar period, I can also understand that some CAs
and their auditors may be waiting, during the BR alloted 90 days, to see if
it may be possible to inspect the location during that period (such as
waiting to see if by May they can visit). I would still encourage full
transparency now, in such cases, as they still signal an awareness of
potential delays, and we can work with the CA to understand the challenges
and limitations, and work towards reasonable solutions for the worst case.
_______________________________________________
dev-security-policy mailing list
dev-security-policy@lists.mozilla.org
https://lists.mozilla.org/listinfo/dev-security-policy

Reply via email to