As I research an upcoming feature on PCI, I've been speaking with a number of retailers and PCI auditors. Here are a few tips you might find useful.
1)Self assessments. CIOs are conducting internal audits of their IT teams and business units to find out who touches credit card data and where they keep it. It's important to get this information from all the stakeholders, particularly business units that take customer orders or use card data to analyze buying trends.
2)3rd-party audits. It's often instructive to bring in outside experts to help you ferret out credit card data. One auditor told me about a major grocery chain that had made significant efforts to purge card data from systems that didn't specifically need it. But when he bought a pack of gum with his credit card and then reviewed the logs of the point of sale system, he found it was recording the full card number and expiration date.
Of course, third-party audits are expensive, so you have to weigh the cost against the potential fines of PCI violation -- along with the risk of a malicious party getting access to that data source.
3)Use tools. One retailer bought a data leak prevention product to make sure intellectual property and other sensitive data didn't leave the network. He also used its discovery feature to crawl his headquarters network and remote offices for repositories of card numbers. He used the findings to approach the business units holding the data to ensure they were following IT policies for encryption.
He also crawls the network regularly for rogue data or noncompliant business units. Which brings us to ...
4)Get your processes in order. Some 99% of PCI compliance revolves around having IT and business processes in place to secure card data. You have to ensure that business units understand IT policies -- and that they're following them. You also may want to tweak business processes to minimize (or eliminate) the use of credit card data wherever possible. For instance, credit card numbers can be replaced with unique identifiers to analyze customer purchases.