Industrial control systems (ICS) play crucial roles in industries like food and agriculture, health care, chemicals, waste and water systems, communications, power, and transportation. Although these environments were not originally designed to be internet-facing, the demand for connectivity and the need to converge with operation and information technologies have given rise to internet-enabled ICS environments.

This connectivity brings cybersecurity risks to ICS systems — critical infrastructure cyberattacks rose by 3,900% between 2013 and 2020. ICS security best practices must be implemented to manage and mitigate these security risks.

What Is ICS in Cybersecurity?

Critical infrastructure systems are enticing targets for cybercriminals. ICS in cybersecurity involves securing these systems from unauthorized access and other disruptions that could result in significant consequences, such as power outages. It protects hardware and software systems with a combination of network segmentation, access control, regular updates and constant monitoring.

ICS security best practices involve prioritizing the operation of critical machinery by ensuring the processes that support its operation remain protected in an evolving cybersecurity landscape. The focus is on preventing incidents, but ICS security can also provide immediate assistance when workers’ safety is at risk. As cybersecurity threats evolve with time, understanding ICS network security and best practices is crucial — from segmenting control networks to enforcing access policies that protect your most critical systems.

Why ICS Security Is Crucial for Organizations

ICS security is critical to business operations for several reasons. In addition to maintaining a robust cybersecurity posture, they help maintain the physical safety of the people who maintain and benefit from critical infrastructure systems. Obsolete cybersecurity in this context could result in the community losing access to essential services.

Globalization and connectivity have streamlined operational processes across industries, but interconnected networks are more accessible to cybercriminals. Many ICS systems were developed before this threat was so significant. A massive 71% of ICS devices have outdated operating systems, 66% have no automatic updates and 64% have unencrypted passwords. As a result, devices are vulnerable to various forms of cyberattacks.

ICS security can effectively protect these systems, making it a vital element of overall security in the following ways:

• Guard critical infrastructure: ICS security protects critical infrastructure that provides the population with essential services. Attacks on crucial business infrastructure can cause financial losses, threats to public safety and physical damage.
• Prevent data breaches: Data breaches in critical infrastructure can have catastrophic results. ICS cybersecurity helps protect sensitive information from unauthorized access and the associated financial and reputational damage.
• Preserve operational continuity: Cyberattacks can cause prolonged downtime and significant expenditure to regain normal operations. ICS security creates redundancy, allowing operations to continue and preventing the ramifications of extended downtime.

The ICS Threat Landscape: What Manufacturers Need to Know

Industrial control systems were once considered relatively safe from cyberattacks — isolated from the internet and protected by obscurity. That’s no longer true. Today, ICS networks are a primary target for sophisticated threat actors, and the consequences of a breach extend far beyond data loss. Production shutdowns, equipment damage, safety incidents, and regulatory exposure are all on the table. Here are the two threat categories every manufacturer needs to understand.

Ransomware Targeting ICS Environments

Ransomware attacks on industrial facilities have grown significantly in recent years, with threat actors increasingly targeting OT networks rather than just corporate IT systems. When ransomware reaches an ICS environment, the impact is immediate: PLCs, HMIs, historians, and engineering workstations can all be encrypted or rendered inoperable, forcing production to halt until systems are restored.

Unlike IT ransomware incidents, OT ransomware recovery is significantly more complex. Restoring control system software, re-validating process logic, and safely restarting production requires specialized knowledge that most IT recovery teams do not have. The result is extended downtime — often measured in days or weeks, not hours.

Key ICS ransomware risks to address in your security program:
• Flat network architecture that allows ransomware to spread from IT to OT
• Unpatched operating systems on HMI and engineering workstations
• Lack of offline backups for control system configurations and historian data
• Remote access pathways (VPN, RDP) that are not properly segmented or monitored

Supply Chain Threats to Industrial Control Systems

Supply chain attacks target ICS environments indirectly — through the software, hardware, and service providers that manufacturers trust. Rather than attacking a facility directly, threat actors compromise a vendor, a software update, or an industrial component, and use that as a pathway into the ICS network.

This attack vector is particularly challenging because it exploits trusted relationships. A software update from a legitimate automation vendor, a remote access session from a support technician, or a replacement PLC component sourced through an unfamiliar distributor can all serve as entry points.

Key supply chain risks to address:
• Third-party remote access without session monitoring or time limits
• Software updates applied to control systems without integrity verification
• Hardware sourced outside of verified supplier channels
• Lack of vendor risk management processes for OT-connected suppliers

Malisko Engineering helps manufacturers evaluate and address these threat vectors as part of a broader ICS security assessment. Our team understands both the automation architecture and the cybersecurity controls needed to reduce risk without disrupting production.

Cybersecurity Practices for Industrial Control Systems

Protecting your ICS system from cyberattacks and related threats requires a multilayered approach. Some notable ICS security best practices include:

1. Control Physical Access

If malicious actors can access your hardware, they can perform various attacks, including delivering malware. Physical access control only allows authorized personnel to enter the relevant areas. Role-based access control sets permissions and privileges based on roles within your organization, which helps prevent human error. You can control physical access with several systems, including biometrics, card readers, multifactor authentication and network segmentation.

2. Understand Each Device in Your Industrial Control Systems

Conducting a complete ICS asset inventory is the foundation of comprehensive ICS security. Your organization can only secure devices if it knows they exist. Comprehensive asset details also allow you to respond correctly to security-related information.

ICS asset inventory goes beyond hardware and software to include the devices’ physical locations. It should also identify the people responsible for managing the devices and evaluate the assets’ significance to the industrial process. Automation simplifies your asset inventory process and lets your security team focus on their core competencies, allowing them to identify any ICS assets connected to the network.

3. Automate Vulnerability Monitoring

Malicious actors use increasingly sophisticated tools to uncover system vulnerabilities quickly and frequently. Automated vulnerability tools minimize their access window. They notify you of any exposed system vulnerabilities so your team can patch them and take quick action to prevent unauthorized access.

Automated vulnerability assessments complement your regular, scheduled ICS assessments tailored to your organization’s needs. Consider the frequency of system changes within your operations and respond proactively to the evolving threat landscape to ensure your automated system can identify new threats.

Key vulnerabilities to focus on include:

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

Along with vulnerability monitoring, implementing incident response plans means everyone has a role in restoring system operations after a cybersecurity incident. These comprehensive plans include procedures to follow, like containment and eradication protocols, communication plans, and recovery steps.

4. Reduce Your Attack Surface Area

Isolate or disconnect your ICS from untrusted networks. ICS network security is one of the most critical layers of your overall cybersecurity posture. Effective ICS network security measures include switching off unused devices, locking down unused ports, and allowing only real-time connectivity to external networks when there is a defined control function or documented business requirement. Use optical separation if one-way communication can accomplish a task. Otherwise, use a single open port over a restricted network path when bidirectional communication is necessary. 

Network segmentation is critical to managing access and achieving network visibility. Without it, attackers can move through the ICS network without detection. Segmentation provides opportunities to identify and prevent threats.

5. Provide Regular Cybersecurity Training

Develop a comprehensive training program that addresses risks and unique challenges associated with ICS environments in your organization. Regular workshops and simulations that mimic specific situations can be conducted to familiarize employees with the threats they may encounter. Some of these threats include social engineering attacks and phishing attacks.

Emphasize the importance of employees identifying suspicious activity, using strong passwords and reporting security accidents as soon as they’re detected. Promoting a culture of vigilance in your organization can minimize threats. 

Make sure you have security staff who frequently look at ICS event data and are trained in ITC environment operations. Proper training will ensure they can differentiate operational technology networks from the IT networks they’ve traditionally monitored. For example, they should be able to identify the differences between ICS networking and conventional IT networks. 

6. Manage Authentication

Malicious actors are increasingly focusing on legitimate credentials, especially highly privileged accounts. Gaining control of these accounts allows adversaries to pose as legitimate users. Multi-factor authentication should be implemented to prevent these issues, and access privileges should be restricted accordingly. Where passwords are necessary, enforce secure password policies.

Using the principle of least privilege can eliminate unnecessary access and minimize the probability of attacks. When only users have access to essential information for their role, attackers have fewer opportunities to attack without detection.

7. Secure Remote Access

Although remote access can be convenient for operations, it can also create significant risks. Be sure to control remote access and implement time limitations properly. Where possible, use two-factor authentication for further security.

Secure Your Industrial Control Systems With Malisko

ICS security is essential to safeguarding critical ICS assets and preventing financial losses. It also prevents data breaches and preserves operational continuity.

At Malisko, we can help you secure your industrial control systems by implementing robust security measures and industry best practices. We provide industrial IT and plant floor control solutions, including industrial cybersecurity services and networking design. Our goal is to help your business comply with industry regulations while providing you with high-quality, tailored solutions and post-project support.

Learn more about our IT capabilities for the manufacturing industry, and contact us for more information. 

ICS Security Frameworks: NIST CSF vs. IEC 62443 — Which Standard Applies to Your Operation?

Securing an ICS network starts with a framework — a structured approach that tells you what to protect, how to protect it, and what to do when something goes wrong. Two standards dominate this space: the NIST Cybersecurity Framework (CSF), widely adopted across U.S. critical infrastructure, and IEC 62443, the internationally recognized standard built specifically for industrial automation and control systems. Here’s how they compare and which one belongs in your security program.

At Malisko Engineering, we help manufacturers assess their ICS security posture against both NIST CSF and IEC 62443 requirements. Whether you’re building a security program from the ground up or validating an existing one, our team of automation and industrial IT specialists can guide your assessment and implementation.