News broke last week that a major retailer was the victim of a massive theft of customer credit card data, in what is becoming an all too common cadence of data breaches. Thieves made off with not just the credit card numbers, but also the CVV and expiration dates. If you listen closely, you can probably hear the machines printing up counterfeit cards. At this point there has been no precise confirmation of the attack vector used to collect the data – and the gory details may never be known, absent some government action and FOIA request. But in light of what is likely one of the biggest data breaches in history it makes sense to reflect on some of the Payment Card Industry’s (PCI) best practices for protecting customer data. PCI is more than just compliance but should be viewed as a catalyst to improve overall network defense and data protection. In this first post we cover high-level PCI & PII practices that can make a difference- in subsequent posts we will decompose into more detail into how the Target Breach could have been prevented.
Protecting the Brand and the Business
The fallout for Target will surely be in the millions of dollars going beyond fines and reimbursements to consumers but to the damage done to the Target brand. Shoppers entrusted their confidence in Target’s information security practices. While Target is doing a good job of notifying customers of the steps they can take to protect their credit ratings, I have seen several shoppers thinking twice about using their credit cards while doing last-minute Christmas shopping — not just at Target but in other retailers and other industries. Undoubtedly customers are more wary than ever to give out credit card data unless they see that “good house keeping” seal of approval that a merchant has tested their POS and back end systems to the best of their ability. This mistrust will also spill over into e-commerce where consumers where already wary of giving out personal data.
PCI Tools for Credit Card Security
Just because a retailer is PCI compliant, that doesn’t mean they’re 100% secure. But maintaining PCI compliance will reduce the likelihood of data theft – make it hard enough for an attacker and they will hopefully move on to a more vulnerable target. Unfortunately the scale of compliance can be daunting for many organizations. Considering the size of last week’s theft – some 40 million account numbers compromised – it’s clear that high-capacity, high-volume solutions are needed. Many existing solutions haven’t kept pace with rate of technology changes, leading to implementers being overwhelmed attempting to rip and replace as they move more of their businesses online.
There are six milestones in the Prioritized Approach to Pursue PCI DSS Compliance. These are necessary but not sufficient for security. Looking at these milestones, it’s clear that the Gateway Pattern can help a retailer (or anyone processing payment card or any other sensitive data) achieve compliance. Furthermore, a gateway can allow faster remediation of legacy systems and applications because it can be inserted into the application stack without significant modification to these existing applications. When new best practices are identified, they can be implemented quickly as well, without being mired in the bureaucracy and expense of custom implementations. This is essential as companies are moving to the cloud for part or all of their transactions. Here are some pointers on how a service gateway can shorten the path to PCI DSS compliance:
- First, remove (i.e. redact) sensitive authentication data and limit data retention. Thieves can’t steal what isn’t there. Card verification numbers, PINs, and magstripe data tracks are not to be stored, as those will enable unauthorized use in more locations via card not present and ATM use. With the increasing dependence on web services for transmitting data across systems and providers, the gateway pattern can help fulfill this requirement by redacting internal fields within a data object (e.g. JSON or XML), ensuring that it isn’t persisted or passed downstream to any application that doesn’t require it.
- Second, protect the perimeter, internal, and wireless networks. This becomes much more challenging in today’s distributed environments. Many payment processing systems use private networks and firewalls to prevent unauthorized access. However, card readers and cash registers are by necessity at the edge, publicly accessible – once a device inside the trusted network is compromised, it can be leveraged to gain additional access. Going a step further, application-specific firewalls or gateways can provide additional network security, which feeds into the next requirement -
- Third, secure payment card applications. Application level security creates an additional internal perimeter to protect against larger-scale data breaches. An application-specific firewall or gateway can provide an additional layer of security that protects against both external and internal attacks. A content attack prevention policy, for example, can limit the spread of an attack that comes from a single compromised system. By monitoring inbound traffic — even from trusted systems — a gateway can help to prevent a content attack such as a code injection masquerading as a valid call from a compromised payment system to a back-end web service or API.
- Fourth, monitor and control access to your systems. Entire books can (and have) been written on this topic, but I’ll highlight a few key benefits of a gateway pattern. First, a multi-tenant gateway allows an organization to separate responsibilities by job function, meaning that a single person doesn’t need to be granted administrative access to every service. Additional logging capabilities provided by the gateway can aid in early detection of malicious activity, alerting to suspicious traffic or other patterns that warrant attention. The gateway can also securely sign the logs to ensure that they haven’t been tampered with.
- Fifth, protect stored cardholder data. This goes deeper than simply encrypting the volume where the data is stored. With the move to cloud storage, data is stored in numerous locations – in replicas and application caches in addition to primary storage. Best practices suggest using tokenization or record-level encryption to protect cardholder data. For the credit card numbers themselves, tokenization provides an added benefit of a secure central vault that contains the mapping between card numbers and tokens that can safely be passed between applications. Randomized tokens have no mathematical relationship to the original cardholder data, so systems that only access tokens are effectively removed from audit scope. This means that the addition of the gateway layer actually reduces audit complexity and cost!
- Finally, finalize remaining compliance efforts and ensure that controls are in place, including ongoing verification and maintenance of compliance posture. This is where the gateway pattern (particularly when it includes tokenization) really shines — by attesting that downstream systems and services never touch cardholder data, the retailer can dramatically reduce the scope of work to be done. Audit and verification costs time and money (best practices include using an outside specialist), so reduction in scope means less complexity and therefore much less cost. In addition to the insurance against potential costs from a data breach, scope reduction can save millions of actual dollars in audit.
Thieves are getting savvy with their attempts to gather cardholder data on all fronts. Attacks on retailers and banks, while difficult to pull off, present potentially enormous return on investment. If successful, they also put a tremendous liability on any organization that doesn’t adequately protect their data. Maintaining customer trust and brand reputation means being a good custodian of data – not just credit cards, but also names, email addresses, and any other personal information. Gaining and maintaining PCI compliance is a good first step in protecting customer data, and with it the corporate brand. Using best practices and tools to do so can accelerate the compliance process and reduce the overall cost of staying compliant. A couple of resources that can help take the next step in using tokenization for PCI compliance: a Tokenization Buyer’s Guide, and a QSA Security Assessor’s guide that explains how using a gateway for tokenization helps to remove systems from audit scope.