1.2.4 An accurate data-flow diagram(s) is maintained that meets the following, including:Shows all account data flows across systems and networks.Updated as needed upon changes to the environment.

Defined Approach Requirements

1.2.4 An accurate data-flow diagram(s) is maintained that meets the following:

• Shows all account data flows across systems and networks.
• Updated as needed upon changes to the environment.

Customized Approach Objective

A representation of all transmissions of account data between system components and across network segments is maintained and available.

Applicability Notes

A data-flow diagram(s) or other technical or topological solution that identifies flows of account data across systems and networks can be used to meet this requirement.

Defined Approach Testing Procedures

1.2.4.a Examine data-flow diagram(s) and interview personnel to verify the diagram(s) show all account data flows in accordance with all elements specified in this requirement.

1.2.4.b Examine documentation and interview responsible personnel to verify that the data-flow diagram(s) is accurate and updated when there are changes to the environment.

Purpose

An up-to-date, readily available data-flow diagram helps an organization understand and keep track of the scope of its environment by showing how account data flows across networks and between individual systems and devices.

Maintaining an up-to-date data-flow diagram(s) prevents account data from being overlooked and unknowingly left unsecured.

Good Practice

The data-flow diagram should include all connection points where account data is received into and sent out of the network, including connections to open, public networks, application processing flows, storage, transmissions between systems and networks, and file backups.

The data-flow diagram is meant to be in addition to the network diagram and should reconcile with and augment the network diagram. As a best practice, entities can consider including the following in their data-flow diagrams:

• All processing flows of account data, including authorization, capture, settlement, chargeback, and refunds.
• All distinct acceptance channels, including card-present, card-not-present, and e-commerce.
• All types of data receipt or transmission, including any involving hard copy/paper media.
• The flow of account data from the point where it enters the environment, to its final disposition.
• Where account data is transmitted and processed, where it is stored, and whether storage is short term or long term.
• The source of all account data received (for example, customers, third party, etc.), and any entities with which account data is shared.
• Date of last update, and names of people that made and approved the updates