Evan Schuman's StorefrontBacktalk

A 403 Labs QSA, PCI Columnist Walt Conway has worked in payments and technology for more than 30 years, 10 of them with Visa.

With the boost in momentum from cloud efforts—and the emergence of PCI-compliant cloud service providers (CSPs)—there is an immediate need to radically rethink what elements need to go into your service level agreements (SLAs) with those Cumulus providers. Consider: If the CSP is responsible for installing vendor security patches (Requirement 6.1), how will you verify that they test the patches first, to make sure they won’t break your application, and then install them promptly?

As a QSA, I’d pay particular attention to patches the vendor identifies as critical, because those have to be installed within 30 days. Will you be able to see a log or other evidence that the patches were installed on all in-scope systems? Another example is your internal and external vulnerability scans. You need to have the CSP provide reporting each quarter on both your complete internal vulnerability scans and your external scans, which an ASV must perform. Another example is the physical security of the vendor’s facility. Can you inspect it to see that the badging, video recordings and visitor logs are all maintained? Because it is quite possible that a cloud provider will have offshore datacenters, what is its plan for you to validate those centers are performing as expected? A brochure might be pretty, but it is not verification of performance.

Let’s start with one basic premise: Using a PCI-compliant CSP is no guarantee that you, the customer (i.e., the merchant), are yourself compliant. The cloud is no more of a silver bullet than any other PCI-compliant service provider or implementing a PA-DSS validated application. What you are buying is an opportunity to make your compliance easier, faster and, maybe, cheaper. What you want to avoid is making compliance more complicated, slower and, maybe, more expensive. A merchant does not “catch” PCI compliance from its CSP—even a PCI-compliant one—like you catch a cold on the subway.

To my way of thinking, a merchant needs to start with a spreadsheet that lists each PCI requirement in one column (and yes, I mean all 240+ requirements). The next spreadsheet column details who is responsible for that requirement, with the options being: the CSP, the merchant or shared. You cannot even begin a serious discussion without this spreadsheet.

Start with those items that are marked “merchant.” Can your organization handle its share of the responsibility for compliance? Will the CSP’s solution reduce the compliance effort and cost sufficiently to justify the expense? As the merchant, do you have the resources to take on the specified responsibilities and manage the cloud provider?

This is also the time to be clear with your CSP about any critical, deal-breaking elements. For example, data privacy or other regulations may dictate that personal data such as payment cards never leave a certain jurisdiction. In these cases, the cloud provider will not be able to move your data between its datacenters in different countries as it pleases. So if you cannot have your data bouncing from the U.S. to Singapore to England to wherever, make it clear upfront.

Next, let’s move to the “CSP” and “joint” requirements. Even though a requirement is marked as being the cloud provider’s responsibility, that does not let the merchant off the PCI hook. I would want to examine the executive summary of the CSP’s Report on Compliance (ROC) to confirm that the PCI assessment covered the scope of services the merchant is buying. Remember, your cloud provider is like any other service provider: You can outsource the processing, but you cannot outsource the responsibility.

Therefore, I’d like now to introduce a third column to our spreadsheet that will further inform our SLA.