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Crucial role of cybersecurity protection for PLCs

Aug. 28, 2024
Programmable logic controllers have become more interconnected and integrated into larger networks—and as a result they’ve become much more vulnerable to cyberattacks.

In today's interconnected world, industrial processes and critical infrastructure—including your operational technology—heavily rely on automation to streamline operations, enhance efficiency, and reduce human error. Programmable logic controllers (PLC) are at the heart of these automation systems, controlling everything from manufacturing processes to power distribution.

However, as PLCs become more interconnected and integrated into larger networks, they also become vulnerable to cyber threats. Understanding the significance that PLC cybersecurity can offer for your organization will help protect PLCs and, by extension, safeguard your critical OT infrastructure.

Understanding PLCs—and the rise in threats

PLCs are specialized computing devices designed to control and automate industrial processes. They execute a set of instructions based on input from sensors and other devices, making them an integral part of industries like manufacturing, energy production, and transportation. PLCs are essential for maintaining precise control over complex systems, but this dependence on automation also makes them a prime target for cyberattacks.

Reader poll: How do you protect your OT?

Cyber threats to critical infrastructure have been on the rise in recent years. Malicious actors, ranging from nation-states to criminal organizations, recognize the potential chaos and destruction they can cause by targeting industrial control systems (ICS) and PLCs. These attacks can lead to operational disruptions, financial losses, and, in the worst-case scenario, endanger human lives.

Common cybersecurity threats to PLCs

Malware: PLCs are not immune to malware infections. Malicious software can infiltrate these systems through various vectors, such as infected USB drives or compromised network connections. Once inside, malware can disrupt normal operations, manipulate processes, or steal sensitive data.

Denial of service attacks: DOS attacks flood the network or PLC with traffic, overwhelming its resources and rendering it unresponsive. This can lead to significant downtime and production losses.

See also: How to choose security for your OT operations

Unauthorized access: Hackers may attempt to gain unauthorized access to PLCs to manipulate settings, steal sensitive data, or sabotage operations. Weak or default passwords and unpatched vulnerabilities can make PLCs an easy target.

Phishing: Social engineering attacks, like phishing, can trick employees into revealing login credentials or executing malicious actions. Once hackers gain access to a network, they may pivot to target PLCs, which is why having control systems security is vital.

Security Issues unique to OT

OT systems are crucial for industrial operations, often interacting with critical infrastructure like power grids and water treatment facilities. These systems are high-value targets for cyberattacks. Key OT cybersecurity issues relevant to PLCs include:

Legacy systems: Many facilities use outdated systems lacking modern security features, making them vulnerable to attacks.

IT and OT convergence: Combining IT and OT networks can create security gaps due to differing priorities and security measures.

Inadequate security measures: Operational continuity often takes precedence over security, leading to weak passwords, lack of encryption, and poor network segmentation.

See also: IT/OT convergence and the making of a modern plant

Remote access vulnerabilities: Increased remote access, especially with the rise of IIoT devices, introduces new attack vectors.

Supply chain risks: Third-party components and software can contain hidden vulnerabilities. Proper vetting and stringent security standards are essential.

Human factors: Employee errors, such as falling for phishing attacks, can introduce vulnerabilities. Continuous training is vital.

Advanced persistent threats: APTs are sophisticated attacks aiming for prolonged network access to gather intelligence or sabotage infrastructure.

Incident response and recovery: Effective plans for quick detection, containment, and recovery from cyber incidents are crucial. Regular testing of these plans ensures readiness.

The importance of cybersecurity measures

Securing PLCs is a multifaceted challenge that requires a combination of technical solutions, policies, and employee training. Here are some crucial PLC cybersecurity measures for protecting your controls system:

Network segmentation: Isolating PLCs from the corporate network can prevent lateral movement by attackers. Creating separate network segments for OT and IT is essential.

See also: Optimizing your OT/IT cybersecurity strategy for an Industry 4.0 world

Access control: Implement strict access controls to limit who can interact with PLCs. Strong authentication mechanisms and role-based access control (RBAC) can help manage permissions effectively.

Regular updates and patching: Keep the PLC firmware and software up to date to address known vulnerabilities. Regularly applying security patches is crucial for reducing the attack surface.

Intrusion detection systems and intrusion prevention systems: Implement IDS and IPS solutions to monitor network traffic and detect suspicious activities. These systems can help prevent attacks or alert administrators to potential threats.

Employee training: Educate employees about cybersecurity best practices, especially those working with PLCs. Training can help prevent common attack vectors like phishing.

Backup and recovery plans: Regularly back up PLC configurations and data. Having a robust recovery plan in place can minimize downtime in the event of a successful attack.

Security audits and assessments: Conduct regular security audits and risk assessments to identify weaknesses in your PLC infrastructure and address them proactively.

As PLCs continue to play a pivotal role in our critical infrastructure, the importance of implementing a PLC security system is paramount. Protecting these systems from cyber threats is not just a matter of business continuity; it's a matter of national security and public safety.

By addressing OT cybersecurity issues and implementing robust cybersecurity measures, organizations can ensure the reliability and integrity of their PLCs, helping to secure the vital systems that power our modern world.

About the Author

Andrew Harris

Andrew Harris is the Michigan team lead at ACS, a member of the Control System Integrators Association. He combines his role as a senior instrumentation and controls engineer with active involvement in business development. Proficient in platforms like Allen-Bradley and Siemens, he orchestrates PLC system lifecycles while identifying and pursuing new business opportunities. He also implements diverse systems, from 8500 HP dyno test cells to manufacturing line installations.