Industrial Control System Protection for Manufacturing

The Challenge: Unpatchable Legacy and Supply Chain Risk

A major global manufacturer faced the dual threat of legacy Operational Technology (OT) and escalating supply chain attacks. Their factory floor relied on Industrial Control Systems (ICS) and SCADA platforms that were over 15 years old, designed for longevity rather than security. Applying security patches required extensive, costly production downtime, making the systems inherently vulnerable.

The Manufacturer’s Core Threat: A ransomware attack breaching the less secure corporate IT network and moving laterally (sideways) to the flat OT network, leading to a catastrophic shutdown of all production lines. The imperative was zero disruption to operations.

Subex Secure’s OT Resilience Solution

Subex Secure implemented a specialized OT security framework focused on compensating for legacy vulnerabilities through network control and behavioral predictability.

Phase 1: OT Asset Visibility and Risk Segmentation

• Passive Asset Inventory: We first used specialized, non-intrusive monitoring to map every PLC, HMI, and machine on the factory floor without affecting their operation.
• Risk-Based Zoning (IEC 62443 Alignment): The flat network was strictly divided. High-risk, unpatchable legacy systems were placed into isolated zones, separated by industrial firewalls acting as secure conduits. The goal was to limit their communication to only what was absolutely necessary for production.

Phase 2: Virtual Patching and Zero Trust Access

• Virtual Patching: For systems that could not be physically patched (due to stability risks), network-level controls were deployed to mitigate known vulnerabilities externally, closing security gaps without touching the core machine software.
• Secure Third-Party Access: Remote maintenance access for external vendors—a major threat vector—was converted to a Zero Trust Network Access (ZTNA) model. Vendors were only granted just-in-time access to the specific machine they needed, and access was revoked the moment the work window expired.

Phase 3: AI-Driven Behavioral Protection

• Industrial Protocol Monitoring: AI models were trained on the specific, proprietary industrial protocols used on the factory floor (e.g., Modbus, DNP3).
• Predictive Anomaly Detection: When a compromised IT endpoint attempted to inject an unauthorized command packet into the OT network, the AI instantly recognized the protocol misuse, predicting a lateral attack, and automatically quarantined the IT endpoint at the point of connection.

Conclusion: Results and Business Value

The customized solution protected the manufacturer’s most valuable assets: their production schedule and uptime.

• Metric: Zero incidents involving lateral movement from the IT to the OT network.
• Operational Uptime: 99.9% production uptime maintained.
• Business Value: Avoided millions in potential revenue losses associated with production downtime and clean-up costs.

By treating OT as a distinct security domain, the manufacturer achieved a security posture that enables both efficiency and resilience.

Is your factory floor protected by an OT-specific defense?