PCI DSS static analysis: catching cardholder data gaps in code
By the Zairen team · · 6 min read
Ask most teams how they handle PCI DSS and you'll hear about their vulnerability scanner and their firewall rules. Ask them where cardholder data actually flows through their application code, and you'll usually get a long pause.
A network scan doesn't read your code
ASV scans are necessary and they're part of the requirement set, but they're testing the perimeter, not the application logic. They won't tell you that a debug log statement is writing full card numbers to disk, or that a "temporary" caching layer someone added last quarter is holding cardholder data longer than your retention policy allows.
Requirement 8 and 10, where code actually matters
Requirement 8 (identify and authenticate access) and Requirement 10 (log and monitor all access) both depend heavily on implementation, not just configuration. Does your access control middleware actually enforce role checks on every route that touches cardholder data, or just the ones someone remembered to protect. Does your logging code capture who accessed what, or just that something happened. Static analysis against the actual codebase answers these questions directly instead of inferring them from a policy document.
The most common gap we see
It's rarely the encryption itself that's wrong. It's the places where cardholder data leaks sideways: verbose error messages that echo back card data, logging middleware that captures full request bodies without redaction, or a "just for staging" code path that got shipped to production and never got locked down. None of these show up on a firewall scan. All of them show up in the code.
Getting to SAQ-ready, continuously
The version of PCI DSS that doesn't hurt is the one where your SAQ is a review of evidence you already have, not a scramble to prove something that was true a year ago is still true now. That means the evidence needs to be tied to the actual requirement, timestamped, and kept current as the code changes, not regenerated once a year under deadline pressure.
Our PCI DSS page covers how the mapping works end to end, or you're welcome to book a demo and bring a real endpoint that touches cardholder data.