11.5.2 Change detection on critical files

The entity needs a deployed change-detection tool (file integrity monitoring is one example) that: warns personnel when critical files are modified without authorization, whether by change, addition or deletion; and compares critical files at least once a week. Applicability: critical files are usually those that rarely change but whose alteration could signal a compromise or its risk. Such tools typically ship with critical files for the operating system preconfigured, while other critical files, such as those of custom applications, must be assessed and defined by the entity (the merchant or service provider). Guidance (good practice) gives examples of files to monitor: system executables, application executables, configuration or parameter files, audit logs held centrally or archived, and other files the entity judges critical. Objective under the customized approach: unauthorized personnel cannot alter critical files without an alert being raised.

Source: PCI DSS v4.0.1, 11.5.2. The statement above is our statement of the clause, read from the published text and cited so you can check it against the official text, not the instrument verbatim. Open PCI DSS v4.0.1 in the compliance library.

Version 4.0.1 is the active version; 4.0 has been retired. Appendix A1 applies only to multi-tenant service providers, A2 only to card-present POS POI terminals that still use SSL or early TLS, and A3 only when a payment brand or acquirer requires it. Which requirements apply to you follows your validation type.