Best Practices: PCI Compliance
Mandated since June 2001, the Payment Card Industry Data Security Standard (PCI DSS) specifies a broad range of technical, administrative and physical security controls for protecting credit card data. While the PCI DSS is made up of only 12 main requirements, they are divided into more than 200 subrequirements, all of which must be satisfied in order to be considered fully compliant.
The PCI DSS provides a well-defined list of security requirements, but many organizations are left with more questions than answers when it comes to determining how best to address each requirement in a manner that will be considered acceptable for PCI compliance.
When approaching PCI compliance, much of the effort can often be handled in-house, but it’s also important to know when to ask for help. Misinterpretation of PCI requirements can lead to costly mistakes. To address the need for expert guidance, the PCI Security Standards Council maintains a program for training Qualified Security Assessors (QSAs). A QSA is not intended to be merely an auditor but is also meant to act as an advisor to organizations working to achieve PCI compliance. QSAs are trained to provide clarification of the underlying intent of the PCI requirements and to assist organizations in identifying reasonable means of satisfying PCI obligations.
The following step-by-step approach for becoming PCI compliant will help the organization avoid many of the pitfalls commonly associated with the process:
1. Educate Yourself.
Read the PCI DSS, preferably several times. Ensure you understand each requirement and try to see the underlying intent of each. Make a list of all the questions you have. Read PCI-related forums and blogs to see how other companies are addressing PCI compliance issues. It’s often helpful to engage a QSA at this point, to provide direction and answers to questions that will inevitably arise during the process of becoming PCI compliant.
2. Determine Your PCI Classification.
Work with your acquiring bank to determine what Merchant or Service Provider classification level applies to your organization for compliance validation purposes. Each acquiring bank is responsible for ensuring the compliance of all of its merchants, so the bank has the authority to determine your company’s PCI classification level. A QSA can help you determine what classification will likely be assigned based upon acceptance channels and transaction volume, but in the end, the bank has the final say in this regard.
3. Perform Data Discovery.
Find out where cardholder data currently exists in your environment. Identify all payment acceptance channels, map out the flow of cardholder data across the network, and identify all places where that data is stored. It is helpful to create a network topology diagram that shows network segments where key systems reside — then map the cardholder data flow onto this diagram for a visual representation of where credit card data is transmitted, processed or stored in your network.
4. Whenever Possible, Eliminate Cardholder Data Instead of Securing It.
Securely dispose of any cardholder data that is not required. This might help to reduce the scope for PCI compliance and will likely reduce the costs associated with becoming compliant. Most companies will still need to retain credit card data but should make sure it’s stored in a centralized, tightly controlled manner. Some organizations that handle only a small volume of transactions might find that it’s easier and less expensive to completely outsource all credit card processing to a third party. If this approach is used, PCI compliance requirements might no longer apply at all (check with your banking institution to be sure).
5. Define the Scope for PCI Compliance.
Now that you know where the cardholder data exists, who has access to it, and how the network is segmented, the scope for PCI compliance can be determined. The entire enterprise (in terms of both network and staff) might not necessarily need to be included within the scope of PCI compliance — and proper scoping is essential to controlling costs for PCI compliance. The PCI DSS applies to all systems that store, process or transmit cardholder data, as well as any systems connected to those (in other words, other systems on the same network segment, not separated by a firewall). Because scope is such a critical aspect of PCI compliance, this is a good point to confirm your scoping approach with a QSA to ensure it will be considered acceptable by PCI standards.
6. Perform a Gap Assessment.
Perform a gap assessment based upon the established PCI scope. Determine whether each requirement is satisfied for all in-scope systems. The PCI Audit Procedures provide additional details regarding how to validate the presence of each required control. Every single requirement must be addressed for full compliance — but compensating controls are allowed, as long as certain criteria are met. Implement Changes to Address Noncompliant Findings.
Build a remediation plan to address noncompliant findings. Implement required controls, write policies, update legal contracts, etc. This step can often turn into an extensive process, depending on the present state of information security and governance in your organization. PCI requirements include technical, physical and administrative controls, so organizations without a well-developed infosec program will find there’s a lot to be built in order to address PCI requirements. This is another point where it makes sense to work with a QSA. A good QSA should be able to help you come up with a cost-effective remediation strategy that is appropriate for your particular business.
8. Perform Quarterly Vulnerability Scanning and Annual Penetration Testing.
Find an authorized scan vendor (see URL below) to scan all Internet accessible systems on a quarterly basis. Remediate any noncompliant findings and rescan until a fully compliant scan report is obtained. In addition to quarterly vulnerability scanning, organizations must also perform penetration testing (network and application layers) at least annually or when significant changes are made to the environment.
9. Provide Validation of PCI Compliance.
Have an onsite audit performed, or complete the self-assessment questionnaire. Submit the Report on Compliance or Self-Assessment Questionnaire, along with the quarterly scan results, to your acquiring bank (for merchants) or to Visa (for service providers).
10. Stay Compliant Through Ongoing Security Maintenance.
Maintain security controls according to guidelines outlined in the PCI DSS to ensure ongoing compliance. There is “safe harbor” protection for organizations that can demonstrate they were in full compliance with the PCI DSS at the time of a breach. This is why it’s important to not only become compliant but also stay compliant.
The following are additional reference materials that are available online and may be useful:
- pcisecuritystandards.org — The official PCI Council Web site, where you can find all of the official documents related to PCI. You’ll want to download and read at least the following:
- Visa Cardholder Information Security Program overview
For the last 10 years, Jeremy Simon, PCI QSA, CISSP, CISA, has served as partner and CTO of Halock Security Labs (www.halock.com). With more than 15 years of experience in information security consulting, Simon’s primary focus in recent years has been providing PCI compliance advisory services, and he has worked with companies of all types and sizes in achieving PCI compliance.