Case Study 5: Retail Chain's Point-of-Sale Breach Prevention

Following several high-profile retail breaches, a major retail chain undertook comprehensive threat modeling of their point-of-sale (POS) infrastructure. Their proactive approach, informed by analyzing others' failures, prevented them from becoming another breach headline.

The threat modeling exercise revealed their POS architecture's complexity—hundreds of vendors, thousands of devices, and intricate payment flows. They adopted a zone-based approach, creating separate threat models for store networks, corporate systems, and payment processing zones. This decomposition made the massive system analyzable while maintaining sight of inter-zone threats.

Several critical findings emerged. First, third-party vendor access for POS maintenance created persistent backdoors. The threat model led to implementing jump boxes with session recording and time-limited access. Second, store networks used flat architectures where compromising one device could access all others. This drove network micro-segmentation initiatives.

The most interesting discovery involved seemingly innocuous HVAC systems. Inspired by the Target breach, they examined all network connections and found HVAC vendors had access paths that could reach payment networks. This led to complete network redesign with proper segmentation and monitoring at all boundary points.

Two years later, forensic analysis of blocked attacks showed multiple attempts matching their threat model scenarios. Attackers tried exploiting vendor access, attempted lateral movement from compromised stores, and even targeted HVAC systems. All attacks failed due to controls implemented based on threat modeling. The investment in threat modeling proved invaluable compared to breach costs others experienced.