With the increasing convergence of operational technology (OT) and information technology (IT), the need for robust security in industrial systems has never been greater. Advanced security features leveraging PLC backplane access present a groundbreaking opportunity to protect industrial control systems (ICS) at their core. However, as with any innovation, this approach brings challenges, particularly around costs, complexity and performance.
This blog post explores the potential of PLC backplane security, addresses concerns about its impact on system performance and provides strategies to manage costs and complexity effectively.
PLC backplane security involves embedding advanced monitoring, validation and anomaly detection capabilities directly into the PLC hardware or its supporting systems. By enabling real-time access to PLC logic and operational data, this approach offers unprecedented visibility and control over industrial processes. It’s akin to bringing endpoint detection and response (EDR) tools into the OT world, with tailored adaptations for the unique requirements of industrial systems.
Monitor PLC logic execution patterns and compare them against a baseline to detect anomalies indicative of cyberattacks. Log every modification made to PLC programs — including source details, timestamps and the exact changes made — to identify unauthorized updates. Use predefined signatures to detect known malicious patterns or logic fragments within the PLC code.
Implement a security layer that scans and verifies all uploaded logic against security policies or digital signatures, rejecting potentially harmful updates. Test new logic in a virtualized environment before allowing it to be executed on the PLC to prevent the loading of malicious code.
Upon detecting malicious code, the system could revert the PLC to a previous known-good state, minimizing downtime and damage. Detect and isolate affected PLCs by blocking communication on the backplane or with other systems to contain the threat.
Capture granular logs — such as backplane communication, I/O operations and logic execution traces — to assist in forensic investigations. Provide operational metrics with security telemetry to offer insights into potential vulnerabilities or weak points in the system.
Deploy decoy routines or configurations within the PLC to attract attackers and study their behavior without risking critical operations. Introduce logic that disrupts or slows down attackers while keeping operations functional, effectively buying time for response teams.
Make the PLC part of the enterprise EDR solution by sending telemetry data to a central security management platform. Enable PLCs to communicate detected threats or anomalies to other endpoints or a SOC for coordinated responses.
Imagine a scenario where every PLC in your facility not only executes its automation tasks but also actively participates in securing the OT environment. They could:
One of the biggest concerns when integrating new security measures into PLCs is whether they will slow down functionality or response times. PLCs are designed for real-time control, where even slight delays can disrupt processes or compromise safety.
How can we implement PLC backplane security while managing costs and operational complexity? Some of the points are mentioned below.
Edge devices or gateways act as intermediaries between PLCs and centralized systems. They handle computationally intensive tasks like anomaly detection, logic validation or advanced analytics, reducing the workload on the PLC itself.
Rather than deploying all security features at once, roll them out in phases. Focus first on high-risk or critical systems, then expand to other areas based on the learnings from the initial implementation.
Integrate new PLC security measures with existing security operations centers (SOC) or security information and event management (SIEM) systems, rather than building new, standalone solutions.
Begin with security features that are easy to implement and require minimal computational resources, focusing on core protective measures.
Features
Benefits
PLC backplane security offers a transformative way to protect industrial systems by providing deep visibility and control. While it introduces challenges in terms of cost, complexity and performance, these can be mitigated with strategic implementation, thoughtful design and leveraging modern technologies.
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