The Co-op Achieves PCI Compliance with Network Segmentation

The Co-operative Group has strong market positions in banking and insurance. The Group employs 110,000 people and has around 4,900 retail outlets. In March 2009 Somerfield joined The Co-operative Group. Somerfield was a high street supermarket with 900 stores in many high street locations throughout the UK.

The Co-operative Group (including the TCG Food stores, Somerfield stores, and Pharmacy business) processes almost 200 million credit and debit card transactions per year, from a store estate of almost 3,500 stores.

The Payment Card Industry (PCI) Data Security Standard (DSS) was developed to encourage and enhance cardholder data security and facilitate the broad adoption of consistent data security measures globally. The standard also required retailers that process large volumes of credit/debit cardholder data to be PCI DSS compliant. The Co-operative Group therefore deemed it necessary to review its store environment with regard to how store devices are segmented as a means of protecting cardholder data in order to work towards PCI compliance.

Segmenting store systems such as tills and guest wireless onto functional VLAN’s to protect cardholder data would require all endpoints to be re-assigned an IP address. The financial implications of achieving this across the 2800 food stores alone was almost cost prohibitive.

Kerv Connect’s experience in understanding the business needs and processes required at the infrastructure layer to achieve PCI compliance had been through working with other customers in the retail sector. In particular Kerv Connect was familiar with the challenges, complexity and cost when network segmentation was introduced into a store environment.

Although network segmentation is not a PCI requirement, it is deemed a mechanism to reduce the scope, cost and difficulty of implementing and maintaining PCI DSS controls. Without network segmentation the entire network would fall in scope of the assessment.

Kerv Connect’s solution to achieve network segmentation and consequently isolate cardholder data was to implement a small firewall with security zones. The stateful firewall that was implemented would filter traffic flows in transparent mode, that is, it would be able to restrict access between defined security zones based on specifically defined policy information without the need to re-address endpoints. The security zones and policy definition was specifically designed to align to the requirements of the PCI DSS standard by de-scoping a large part of the store environment including the wireless infrastructure.