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.

Merchants everywhere love to connect with their customers by E-mail, Twitter and SMS. Such regular and personal communication helps build a strong relationship and loyalty. The problem is that customers sometimes take this communication a bit too far. They can E-mail, tweet or text their payment-card information to a merchant without being asked. When this happens, the merchant is left with a very painful, but very straightforward question: What do I do with that transaction?

If a merchant rejects the transaction, the customer may be offended, confused or just go away. These are bad outcomes for the business, whether it is a retailer or a charity. On the other hand, processing the transaction means the particular communication system (and everything connected to it) is now transmitting cardholder data. This is the case even if the customer wasn’t asked to provide the information. Processing the transaction can increase the merchant’s PCI scope, thereby leading to an even worse outcome with broad implications for the enterprise.

To solve this problem, we need to understand PCI scoping, the merchant’s own policies and its procedures when unwanted data comes streaming over an open public network.

Every merchant knows one of the most important steps in managing PCI compliance (and maintaining sanity) is to limit scope. That is, minimize the number of systems that store, process or transmit cardholder data (a.k.a., the cardholder data environment), along with any systems that connect to them. The next step is to isolate these systems and processes from the rest of the environment.

This is a great plan that can—but does not have to be—easily defeated by customers’ unsolicited E-mailing or texting of their payment-card information (i.e., the primary account number [PAN]). Everything depends on what the merchant does right after that unsolicited data comes into its network.

The first step is to look at the merchant’s policies. Does it state explicitly what are the approved payment channels? I like to see a statement like: “Mega Corp. accepts card present, mail order, telephone order and Web transactions at company locations.” That is, does the merchant exclude channels like E-mail and/or even fax?

The next step is to check the actual practices. Here is the painful, but unavoidable part: The merchant cannot process the errant transaction. If it does, then regardless of the policy, that merchant is actually accepting and processing E-mail, text or Twitter transactions. That means those systems are in the merchant’s PCI scope.

I see this situation all the time.