Deploy PCI-DSS Compliant Payment Infrastructure on Azure

Architecture Overview

This architecture implements the core PCI-DSS requirements through Azure’s security services and network architecture. The foundational principle is reducing the cardholder data environment (CDE) to the smallest possible scope. By strictly segmenting the network and limiting which systems can access cardholder data, you reduce the number of systems subject to PCI-DSS controls and simplify both compliance audits and ongoing monitoring.

Network segmentation creates three distinct zones: a DMZ that handles external traffic and terminates TLS, an internal zone for application logic that does not touch card data directly, and a secure zone where cardholder data is processed and stored. Traffic between zones passes through firewalls with explicit allow rules, and the secure zone has no direct internet access. This segmentation is the single most important PCI-DSS control because it limits blast radius if any single component is compromised.

Continuous monitoring replaces the traditional model of point-in-time compliance assessments. Security Center continuously evaluates your Azure resources against PCI-DSS requirements and flags configurations that drift out of compliance. Sentinel aggregates and correlates security events across all three zones, providing the SIEM capability that PCI-DSS requires for incident detection and forensic investigation.

Network Zones

Azure Virtual Network with network security groups enforces zone separation. The DMZ subnet hosts the Application Gateway with WAF, which inspects incoming traffic and terminates TLS. The internal subnet runs application servers that implement business logic. The secure subnet contains the database and any systems that process cardholder data. Each subnet’s security group permits only the traffic necessary for that zone’s function.

Data Protection

Azure SQL Database stores cardholder data with transparent data encryption at rest and TLS for data in transit. Dynamic data masking ensures that application users who query the database see masked card numbers unless they have explicit unmasking privileges. Key Vault manages encryption keys and database credentials, with access policies that restrict which services and administrators can retrieve secrets.

Compliance Monitoring

Security Center runs continuous compliance assessments against PCI-DSS benchmarks, scoring your environment and flagging resources that fall out of compliance. This provides an always-current view of your compliance posture rather than relying on periodic audits. Alerts trigger when configurations change in ways that affect compliance status.

Security Event Management

Sentinel collects logs from every component in the architecture: Application Gateway, network security groups, Azure SQL audit logs, Key Vault access logs, and identity events. Correlation rules detect patterns that indicate potential breaches, such as repeated failed authentication attempts followed by a successful login, or unusual database query patterns against cardholder data tables.

Common Customizations

• Add tokenization: Extend the prompt to include a tokenization service that replaces card numbers with tokens, further reducing the CDE scope and simplifying compliance.
• Implement Azure Private Link: Request Private Link endpoints for Azure SQL and Key Vault to eliminate any data transit over public networks, even within Azure’s backbone.
• Add automated remediation: Ask for Logic Apps or Azure Functions that automatically correct non-compliant configurations when Security Center detects them, reducing the time between detection and resolution.
• Enable PCI-DSS reporting: Request automated generation of compliance evidence reports from Security Center findings for quarterly assessor reviews.