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Platform as a Service and PCI



Achieving PCI compliance can be a complex, time-consuming, and expensive undertaking, but the right approach can make it substantially less burdensome. In this brief paper we provide some critical background and recommendations intended to help you make the best possible decisions regarding PCI for your PaaS-based application. If you currently accept, or are contemplating accepting a payment card on your web application, this document is for you.


Many of the applications running on Engine Yard are primary revenue sources for their owners. While some companies monetize these applications via advertising, many of them deliver premium services or process transactions that require payment from the end-user. To facilitate these transactions, applications must provide a payment mechanism, and in the online world these transactions are often conducted using payment cards (cards or devices that bear the logo of American Express, Discover Financial Services, JCB International, MasterCard Worldwide, or Visa, Inc. 1 ) Given the potential for fraud in the fast-moving, often-anonymous environment of the Web, it is not surprising that there is substantial regulation and oversight of payment card use designed to protect both companies and consumers. “PCI DSS” is shorthand for the Payment Card Industry Data Security Standard, the regulatory body and standard for ensuring that the use of payment cards is as secure as possible.

PCI Overview

PCI certification is required for any organization that processes, transmits, or stores cardholder data. This includes merchants and service providers. The certification is designed to safeguard payment card data from theft through increased controls and processes over how the data is handled and protected. The standard applies to all organizations that hold, process, or exchange payment card information from any branded card. If a company’s systems handle a payment card number, even if it is just for a brief moment (e.g. customer types credit card into the company’s web form; company stores credit card in memory; company sends credit card to payment processor; company deletes credit card from memory), the company is required to be compliant. The number of requirements necessary to be compliant is the same no matter how many payment card transactions that you process, however the attestation approach will be different based on your annual volume.

Achieving Certification

To achieve certification, a company must first understand and document its cardholder data environment (CDE), including all systems that process, transmit, or store payment card numbers. Along with these primary systems, the organization must take note of all other support systems that may interact with the CDE (e.g. security monitoring, key management, LDAP, etc.), as well as all other systems that may not be directly involved in the payment card transaction, but which are not separated by network controls. In general, if a particular system interacts or can reach the CDE, that system needs to be documented. Once documented, the network diagram will guide the organization’s PCI scope. With the scope defined, the company must ensure that specific control activities are designed and operating effectively for PCI’s key security objectives:

  • Maintain a secure network
  • Protect cardholder data
  • Maintain a vulnerability management program
  • Regularly test and monitor for vulnerabilities
  • Maintain an information security policy

The type of testing required, and the level of assurance to be demonstrated is related to the number of payment card transactions executed annually:



Merchant LevelMerchant DescriptionRequirement
Level 1> 6,000,000 transactions per year across all channels, including e-commerce
  • Annual onsite PCI data security assessment by a QSA or internal auditor if signed by an officer of the company
  • Quarterly network scans
Level 21,000,000 – 5,999,999 transactions per year across all channels, including e-commerce
  • Annual self-assessment 2
  • Quarterly network scan
Level 320,000 – 1,000,000 e-commerce transactions per year
  • Annual self-assessment
  • Quarterly network scan
Level 4< 20,000 e-commerce transactions annually and < 1,000,000 transactions per year across all channels
  • Annual self-assessment
  • Annual network scan



The Challenge

Achieving PCI certification is difficult for many reasons:

  • The PCI DSS requires that not only the CDE be in scope for controls (which includes the people, process, and technology components), but also any system that is connected to the CDE, including support systems.
  • Controls require supporting process documentation and evidence.
  • PCI requirements are highly prescriptive and do not take into consideration your risk assessment process in defining the controls environment. This means that your organization must follow the requirements exactly as stated. If you cannot meet the requirements, you may have to look into compensating controls.
  • Although compensating controls are permitted in the PCI DSS, they are difficult to justify and still must meet or exceed the intent of the control that they are compensating for. Often compensating controls are much harder to implement than just meeting the requirements of the original control.
  • There are over 200 requirements within the DSS, and they are all-ornone— you either have them in place and functioning properly, or you do not and thus have a deficiency. A fail of any control is a fail of the entire certification.
  • Depending on the role of any third-party that your business engages with, the third-party may be required to comply with a portion of the PCI requirements for you to be in compliance.
  • PCI is a point-in-time audit performed annually, but to truly sustain the controls and pass the yearly audit, an organization must be disciplined and continually monitor the operating effectiveness of their controls.

According to Verizon’s “2011 Payment Card Industry Compliance Report”3 on PCI, “only 21 percent of organizations were fully compliant at the time of their Initial Report on Compliance (IROC).” In our experience, PCI compliance is often expensive, difficult, time-consuming, and simply cannot be successfully tackled as a one-off project. PCI is not something that can be “crossed off the list” once you attain your initial certification. If you are going to tackle PCI compliance, the effort must be a part of your ongoing compliance program in order to maintain a successful year on year certification.

Making PCI Tractable

There are two fundamental paths a merchant can take to achieve PCI compliance for an ecommerce application. The first, which we highly recommend, is to outsource all payment card data handling to a compliant third-party thus greatly reducing your compliance burden. The second path, achieving PCI compliance directly, is best attained through technical solutions that focus on reducing your compliance scope.

Process Evaluation and Streamlining

First, you should rigorously evaluate your cardholder data handling needs and practices. Ask yourself:

  • Where are we collecting the data?
  • How are we storing the data?
  • Who has access to the data?
  • Why are we collecting the data?
  • What do we do with the stored data?
  • Are there data elements that we do not need to collect?
  • What do we lose by not collecting this data?
  • Does system X require access into the CDE?
  • Does user X require access into the CDE to perform their job?

Depending on the results of this evaluation, consider streamlining or altering payment or other processes in order to reduce the number of payment card data repositories and systems that are need to be compliant. Modifying these business processes to not collect and retain PCI-relevant data can have a significant impact on scope reduction, and lowers your overall risk profile.


Due to the demands of PCI compliance, most of the traditional payment processors, along with a number of technology companies, have pushed heavily into offering up full or partial outsourcing models for payments. These include:

  • A transparent redirect – The approach allows the merchant to keep the look and feel of their site consistent, while outsourcing the entire capture
  • the card to a third-party processor. This method greatly reduces the compliance burden and is the recommended approach, especially for smaller organizations. With this design, the cardholder data never touches your infrastructure. Additionally, most third-parties use aspects of tokenization to still allow you to track payment card payments and related metrics, without actually requiring the storage of the card number on premise.
  • An embedded payment page – This approach places a branded payment processors page within your Site during the payment process. This effectively does the same thing as a transparent redirect, but you may lose some of the look and feel of your site. Both the traditional payment processors, and alternative ecommerce payment services like PayPal and Google Wallet offer this type of service.


  • The easiest and most affordable way to achieve PCI compliance.
  • The cardholder data never touches your environment, thus greatly reducing your risk and liability.
  • Simple to maintain assessment year over year.
  • Payment card information is secured by payment processors that meet high standards of security processes and controls.

Technical Solutions

If outsourcing will not work for your business situation, the alternative is to attain PCI compliance directly. Realize that no matter how well attested and compliant the platform and infrastructure underneath your application is, you still will be responsible for drafting a Report on Compliance. Thus, no IaaS or PaaS provider, including Engine Yard, can achieve compliance on behalf of a customer. Rather, what a cloud provider can do is maintain effective security architecture and supporting security management practices such that they do not prohibit you from meeting your compliance obligations. For example, PCI requires that all interactions with the Cardholder Data Environment (CDE) be logged. In order for you to meet this obligation, your cloud provider would be required to log the interactions of their employees against your systems, and be able to demonstrate this to you or your Qualified Security Assessor (QSA). Additionally, you will want to consider if the cloud provider’s architecture supports a PCI compliant solution, and if so, how? For example, what considerations would need to be made if your cloud provider deploys with a multi-tenancy versus single-tenancy approach?

Depending on the architecture, you may need budget time and money to develop compensating controls.

As stated earlier, if you prefer to not utilize an outsourcing approach, you should direct your attention to scope reduction. You can consider a variety of technical options; however note that none of these will reduce the PCI requirements, just lessen the number of systems and applications where the requirements may apply. These approaches include:

  • Network Segmentation
  • Tokenization
  • Point to Point Encryption

Network Segmentation

Segmenting the CDE from the remainder of the corporate network is not a PCI DSS requirement, however it is recommended as a method to reduce PCI scope, cost, and risk. Proper network segmentation can ensure the following:

  • Network broadcasts are contained to the local network.
  • Internal network structure is not visible from outside the subnet.

Organizations can create segmented networks using a variety of methods including network-based controls (e.g. FWs, VLAN or ACLs), logical partitions (LPAR), or virtual segmentation.

Network segments must be locked down such that only traffic that has a business justification is allowed into or out of the defined PCI network. This includes validating that:

  • The network rules into and out of the zone are specific to individual systems and ports, and contain a default deny rule.
  • All connections and network traffic are identified, inventoried, and documented.
  • As requirements change or new systems come online, updates to the PCI network diagram and rule base are created.
  • A bastion host or VPN is used in controlling access via dynamic or unknown locations.


  • Network segmentation is the most common solution to reduce system scope for PCI.
  • Payment card data is restricted to networks “isolated” from the rest of the corporate network thus not only reducing your PCI scope, but also decreasing your risk.
  • Systems and devices outside the PCI network can be considered out of scope.


Payment tokenization is the process of substituting sensitive cardholder data (i.e. the Primary Account Number) with a unique, non-PCI relevant surrogate value (or token). Cardholder data cannot be derived from the token, as the token is generated using an additional element other than the account number. The only association between the cardholder data and the token is through a reference table stored in a secure repository. With the exception of the first six digits or the last four digits of the Primary Account Number, the cardholder data is never in clear text form on any system outside of the entry point and the tokenizing application. Payment tokenization can be performed in-house, and developed as an Enterprise service, or it can be outsourced through a secure payment gateway.


  • The point where payment card data is sent to be tokenized must be protected and would remain in scope for PCI DSS compliance, but much of the rest of the infrastructure could be considered out of scope.
  • If a payment token is exposed, the cardholder data remains safe

Point to Point Encryption

Point-to-Point Encryption is the encryption of cardholder data from one point (e.g. the point of input or acceptance) to another point (e.g. a point beyond the merchant or accepting entity’s network). The information traveling between two points is encrypted, and the merchant does not have access to the decryption keys or process.


  • Effective in maintaining the security of cardholder data including storage, processing, and transmission.
  • Outsourced technology provider is responsible for securely handling cardholder data and merchant does not have access to encryption keys.

In summary, before moving forward with PCI, take a moment to consider your business processes, your compliance goals, and what opportunities may exist to either fully outsource the payment process or reduce your scope. Taking the time to perform this analysis can save you a lot of pain later on.



Meeting PCI Compliance in the Cloud

As Cloud adoption has grown from niche uses, to larger scale operations, security and compliance concerns have also trended upwards. Initial reaction to compliance in the Cloud usually was best summarized as, “No chance”. However, security processes and technologies continue to mature, and the security of the Cloud has caught up, if not surpassed, what can be provided within a traditional data center environment. With that said, the PCI burden will remain extensive whether you decide to move your payments to a Cloud environment or not.

Implementing a PCI Compliant Application on a PaaS

With the Engine Yard PaaS model, Engine Yard and its customers maintain joint responsibility for aspects of security. For example, both our support organization and our customers have the ability to perform super-user level functions on specific instances. Additionally, both parties have the ability to provision accounts that can access these instances. To maintain compliance, Engine Yard and its customers need to ensure that accounts that have access to the customer’s instances are appropriate, and that there is a defined process to procure and remove access. You should work with your PaaS to understand the delineation of security responsibilities, and what their security management processes are.

Additionally, have an open dialogue with your PaaS about the state of security on their platform. Cloud security is an evolving field, and your PaaS provider should have a point of view and a vision. Evaluate:

  • Have they formally assigned a leader for security in their organization?
  • Do they have an information security policy?
  • Do they have an incident response plan?
  • Do they perform regular security audits against their platform?
  • Do they have a security roadmap? When engaged, do they listen to your needs, and garner your feedback?
  • Do they have the capability to allow you to partner with other cloud security providers?
  • Do they possess, or are they looking to achieve a certification such as SAS 70 or SSAE16?
  • Do they play a role in the broader cloud security community?

Why Engine Yard?

Engine Yard provides multiple platforms that can grow with your organization. Through our design, we provide a number of security controls that help to keep your application protected. We listen to our customers, participate in the cloud security community, and continue to develop and evolve our platform to meet your security needs. When considering compliance in your current cloud provider, or considering moving to a Cloud environment, consider both the inherent security benefits of the Cloud, but also the security design and process decisions the PaaS provider has made. Engine Yard’s strengths include:




Your business is on the Web either because it is either fundamentally a new type of offering that is uniquely enabled by the Web or because the Web is the best way to market and/or deliver your offering. In either case, you need to make money and be paid for your offering, and often there is no better way than the fast, selfservice payment card transaction. Depending on your payment strategy, there are a number of ways to address PCI compliance. We look forward to working with you to find a solution that meets your needs on the Engine Yard

  1. Payment Card Industry (PCI) Data Security Standard. https://www.pcisecuritystandards.org/documents/pci_dss_v2.pdf
  2. MasterCard is the exception, and requires Level 2 merchants to follow the same requirements as Level 1 merchants – including an annual onsite assessment.
  3. Verizon 2011 Payment Card Industry Compliance Report. http://www.verizonbusiness.com/resources/reports/rp_2011-payment-card-industry-compliance-report_en_xg.pdf

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