ICS Cybersecurity Guide: Managing Risk in Industrial Operations

ICS Cybersecurity Guide: Managing Risk in Industrial Operations

In today's digitally connected world, industrial control systems (ICS) play a crucial role in managing operations across various industries.

These systems are the backbone of industrial sectors, running everything from manufacturing processes to energy distribution. As these systems and the edge devices around them become more connected, they also become more susceptible to unplanned downtime from a cyberattack or operational misconfigurations.

In this comprehensive guide, we’ll delve into the world of ICS cybersecurity, including the challenges, best practices, and strategies to keep industrial operations resilient.

Understanding ICS (and OT)

Industrial control systems are specialized computer systems used to control and monitor industrial processes. They include supervisory control and data acquisition (SCADA) systems, distributed control systems (DCS), and programmable logic controllers (PLCs). These systems ensure the smooth operation of the businesses that fuel our daily lives, including power plants, water treatment facilities, manufacturing facilities and transportation networks. 

While many people use the terms operational technology (OT) and ICS interchangeably, industrial control systems are actually a subset of OT, controlling a physical process itself via SCADA systems with human-machine interfaces (HMIs) or programmable logic controllers (PLCs). Anything tangential to the process, such as the software embedded in equipment or added for control, management and monitoring would be considered “OT”, but not “ICS”. The graphic below conceptualizes these differences.

Example of OT & ICS Systems

The Evolving ICS Risk Landscape

Control systems were traditionally isolated from external networks, but increased connectivity and the rise of the Internet of Things (IoT) has exposed them to both cyber threats and operational misconfigurations. The impact of an ICS disruption, regardless of the source, can result in physical harm, environmental damage and lost revenue.

Malware & Zero-Day Vulnerabilities

Malicious software designed to infiltrate ICS networks, such as TRITON, Industroyer, NotPetya and Stuxnet, has shown the devastating impact it can have on critical infrastructure.

Attackers actively search for unknown vulnerabilities in ICS software and hardware to exploit them before they are patched. Make sure you have access to the best ICS threat intelligence to ensure you build in detections for zero-day exploits before they are public.


Network Misconfigurations & Process Anomalies

In modern ICS environments, various subsystems and components are connected to optimize operations. This means that an issue in one part of the system can cascade to other areas. A network misconfiguration or process anomaly in one part of the network can quickly spread and impact critical processes.

Network misconfigurations, such as improper firewall rules or insecure device settings, can inadvertently expose critical components of the ICS to unauthorized access or manipulation. Similarly, process anomalies, including unexpected deviations from normal system behavior, can disrupt industrial processes and cause downtime.


People: Phishing, Social Engineering & Disgruntled Employees

Cybercriminals can use tactics ranging from a basic phishing email to complex social engineering schemes to trick employees into revealing login credentials and gain unauthorized access to ICS systems.  

Disgruntled employees or contractors with access to ICS systems can pose a significant security risk. Continuously cleaning up old user accounts, applying the principle of least privilege and spot checking your systems after third-party vendor access can help reduce this risk.


Best Practices for ICS Cybersecurity

1. Create an ICS Asset Inventory

Begin by creating a comprehensive inventory of all assets within your ICS environment using a continuous monitoring tool. Understanding your assets is the first step in protecting them. A good asset inventory should include:


Identify and list all devices connected to your ICS network, including controllers, sensors, and communication equipment.

Software and Firmware

Document all software and firmware versions running on your industrial systems. Keep track of updates and patches.

Communication Flows

Map out how data flows between devices and systems. Identify potential entry points for cyber threats.

To learn more about how a well-maintained asset inventory lays the foundation for effective risk management and cybersecurity measures, check out our guide below.

2. Deploy Continuous Monitoring for Industrial Networks

Deploying continuous monitoring for industrial networks is crucial for maintaining the security and integrity of critical infrastructure. Select a robust monitoring solution that makes sense for your unique ICS environment. Implement network sensors and endpoint monitoring tools strategically throughout your network to capture real-time data on traffic patterns and anomalies.

To ensure the effectiveness of continuous monitoring, it's essential to maintain and update the monitoring system regularly, keeping pace with evolving threats and vulnerabilities. By establishing continuous monitoring as a core element of your cybersecurity strategy, you can proactively safeguard your industrial networks and protect critical assets from cyber threats.


3. Conduct Regular ICS Vulnerability Assessments

Establish a vulnerability assessment schedule tailored to your organization's needs, considering factors like the evolving threat landscape and frequency of system changes. Utilize specialized vulnerability assessment tools and methodologies designed for ICS environments to identify vulnerabilities in hardware, software, and configurations. Important vulnerabilities to focus on might include:

  • Unpatched software: Identify software and firmware that require updates or patches and determine whether to patch or mitigate based on potential impact.
  • Insecure configurations: Review device and system configurations for security weaknesses. Ensure that default passwords are changed, unnecessary services are disabled, and access controls are in place.
  • Unencrypted communications: Assess the use of encryption for data transmitted between devices and systems.

Once vulnerabilities are identified, prioritize mitigations based on their potential impact and likelihood. To see how this might look in practice, check out our video “Merging Asset Data to Unite Security & Operations Teams”.

4. Segment Your ICS Networks

Segmenting industrial networks is a vital practice for enhancing cybersecurity. To begin, identify the most critical assets, or “crown jewels”, and the potential attack vectors. Once identified, create network segments based on these criticality levels, isolating high-value assets from less critical systems. Use firewalls, access controls, and intrusion detection systems to enforce strict separation between these segments.

You should also limit inter-segment communication to only essential data flows and regularly monitor and update segmentation configurations to adapt to changing operational needs. Make sure you are also using technology that can validate whether ICS network zones are working as they should.

To learn more about how to implement segmentation in your ICS networks, read our blog post on the topic.


5. Provide Regular Cybersecurity Training

Develop a comprehensive training program that addresses the unique challenges and risks associated with ICS environments. Conduct regular workshops and simulations to familiarize employees with the specific threats they may encounter, like phishing attacks and social engineering tactics.

Emphasize the importance of strong password management, the recognition of suspicious activity, and the reporting of security incidents. Ultimately, fostering a culture of vigilance in your workforce will minimize threats from the People part of the equation in ICS.

6. Create and Test Incident Response Plans

Start by assembling a dedicated incident response team with defined roles and responsibilities and developing a comprehensive incident response plan outlining the procedures to follow in case of a security event, including communication plans, containment and eradication protocols, and recovery steps.

Tabletop exercises and simulations are a great way to test the response plan's effectiveness in various scenarios, allowing your team to practice their roles and improve their incident response skills. After each exercise, conduct thorough debriefs to identify areas for improvement and refine the plan accordingly.


Future Trends in ICS Cybersecurity

The future of ICS security is marked by several significant trends poised to reshape it forever. Here’s what to watch:

AI and Machine Learning

The integration of artificial intelligence (AI) will revolutionize threat detection and response, enabling predictive analytics and proactive protection for ICS environments.


Blockchain technology has the potential to enhance data integrity, authentication, and secure communication within ICS networks.

Cloud Integration

Migrating some ICS functions to the cloud will provide scalability and flexibility but will also bring new security and privacy challenges that must be addressed.

Regulatory Compliance

Cybersecurity regulations aimed at critical infrastructure organizations are accelerating globally, with more stringent and enforceable standards coming out every year.


The digital world we live in opens the door for all types of disruptions inside critical operations. Protecting critical infrastructure is not just a matter of compliance; it's a matter of national security and public safety. By implementing robust ICS cybersecurity measures and staying informed about emerging threats and technologies, organizations can secure their industrial systems and preserve our way of life for generations to come.