EvidenceSheet
PCI DSS v4.0.1 · Req 1: Network Security Controls

1.2.4 Accurate data-flow diagram for account data

The entity must keep one or more accurate data-flow diagrams that (a) show every path account data takes through networks and systems, and (b) are revised as required when the environment changes. Applicability: a data-flow diagram, or another technical or topological solution identifying how account data moves across systems and networks, can meet this requirement. Objective under the customized approach: a picture of how account data travels between system components and over network segments is kept and can be produced.

Source: PCI DSS v4.0.1, 1.2.4. 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.

4
artefacts
1
held by a system
2
at each review
moderate
to go live
SIEM / log platform
where the evidence lives
teal = a system already holds it · olive = produced at each review. To go live: easy when half or more of the artefacts are already held by a system, moderate from a quarter to a half, hard below a quarter.

These are the artefacts auditors commonly ask for on this requirement, our guidance rather than text from the standard. Your assessor decides what is sufficient in your context, and asks for samples across the period when a report covers one.

system holds itEvidence a system already holds

  • Revision log with update dates and approvers following environment changes · SIEM / log platform

periodic reviewEvidence produced at each review

  • Reconciliation of the data-flow diagram to the network diagram · Cloud console / configuration management
  • Interview notes with application owners confirming each acceptance channel is represented · Data governance / DLP tooling

governing documentDocuments that govern the control

  • Data-flow diagram(s) tracing account data from entry points through authorization, capture, settlement, storage and backup · Policy repository / GRC workspace

First move

Start with the 1 of 4 artefacts that already live in a system (SIEM / log platform); keep the periodic reviews but log each one as a dated record with a named reviewer.

Common gaps auditors find

Do this for your whole sheet

Paste the rows you run your controls from and get this mapping for every control at once, with the periodic-review ones flagged and a first move per row. No account for the first run.

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1.2.3 Accurate network diagram of CDE connections · 1.2.5 Allowed services, protocols and ports justified