PCI scope explodes when card data and supporting systems share flat networks and shared identity. Segmentation—and keeping data out of systems that do not need it—is still the highest-leverage move.
Define the CDE clearly. Use account/subscription/project isolation where possible, private connectivity, strict ingress/egress, and separate CI/CD deploy paths into scoped environments.
Logging, key management, and change control must be continuous. Assessors ask for evidence of how systems behave over time, not only architecture diagrams.
Cloud makes segmentation easier and easier to get wrong. Treat scope reduction as a platform design goal from day one.
Maintain a living data-flow diagram that matches infrastructure-as-code.
Limit who can change security groups/firewall rules that guard the CDE; every change should leave an audit trail.
Rehearse evidence export quarterly so assessments do not become archaeology projects.
Key takeaways
- Reduce CHD scope with clear trust boundaries before buying more tools.
- Segmentation must be technically enforced and evidenced—not only drawn.
- Tokenization and managed payment services often shrink scope more than DIY.
FAQ
Is a VPC enough for PCI segmentation?
Not by itself. You need controlled connectivity, identity boundaries, logging, and proof that out-of-scope systems cannot reach CHD stores.
What fails PCI cloud reviews most often?
Flat networks, shared admin jump boxes into CDE, weak key management, and incomplete flow diagrams that disagree with the live environment.