ICS Security: Critical Challenges and Security Best Practices

Igal Zeifman
Igal Zeifman

7  min read | min read | 18/07/2023

What Is Industrial Control Systems (ICS) Security

Industrial control systems (ICS) security refers to the protection of industrial control systems, a type of operational technology (OT) used to automate and control industrial systems.
These systems include supervisory control and data acquisition (SCADA) systems, distributed control systems (DCS), and other smaller control system configurations such as programmable logic controllers (PLC).

ICS security is growing in importance because ICS systems are increasingly targeted by cybercriminals who recognize their strategic importance and high damage potential. A single successful attack could have disastrous consequences, disrupting essential services, causing economic damage, and even causing physical harm to people or equipment.

Despite the high stakes, many organizations struggle to achieve effective ICS security. This is due to a variety of factors, including the complexity and inflexibility of these systems, the rapid pace of technological change, and the lack of skilled cybersecurity professionals. As a result, many ICS remain vulnerable to attack.

Common Vulnerabilities in ICS

Insecure Networks and Protocols

Many ICS technologies were designed in an era when cybersecurity was not a major concern. As a result, they often lack basic security features such as encryption, authentication, and access control. This leaves them exposed to a wide range of cyber threats, from data theft to denial of service attacks.

Moreover, the increasing interconnectivity of ICS with business IT systems and the internet has amplified these risks. While this interconnectivity can enhance operational efficiency and enable remote monitoring and control, it also provides potential entry points for attackers.

Outdated Software and Hardware

ICS is commonly based on legacy systems that were not designed with cybersecurity in mind. These systems often lack the latest security features and in some cases, are no longer supported by the vendor, making them easy targets for cybercriminals.

Furthermore, updating these systems can be a complex and risky process. In many cases, it can result in downtime, which is unacceptable in critical infrastructure environments where continuous operation is essential. Moreover, for a number of reasons, many ICS environments are air-gapped by design, which prevents remote/OTA patching. As a result, many organizations choose to continue using outdated systems, accepting the associated security risks.

Insider Threats

In the context of ICS, insider threats can come in many forms, from disgruntled employees seeking revenge to careless staff who inadvertently expose systems to risk. Regardless of the intent, insider threats can cause significant damage, including data loss, system disruption, and reputational harm.

To protect against insider threats, organizations need to implement robust access control measures, monitor user activity, and provide regular security awareness training. Additionally, they need to foster a culture of security where every employee understands their role in protecting the organization’s ICS.

Supply Chain Vulnerabilities

The ICS supply chain represents the software, hardware, and third parties that ICS infrastructure depends on for ongoing operations. Supply chain vulnerabilities can arise from various sources, including insecure software or hardware components, third-party service providers with insufficient security measures, and insecure physical transportation of equipment.

Software supply chain vulnerabilities are a particular concern in light of the increasing sophistication of attackers and global-scale attacks (e.g., Solarwinds and Kaseya). For example, an attacker could compromise a software update from a trusted supplier, infecting systems with malware while appearing to be a legitimate update. To mitigate these risks, organizations need to implement rigorous security practices, including secure coding, vetting of third-party software, and regular auditing and patching which – as mentioned above – is an issue.

Poor Physical Security

Without proper physical security measures, unauthorized individuals could gain access to sensitive areas and tamper with equipment or steal data. This is particularly concerning in the case of critical infrastructure, where physical sabotage could have devastating consequences.

Despite this, many organizations overlook the importance of physical security, focusing instead on cybersecurity measures. However, the two are intrinsically linked—a failure in physical security can easily lead to a cybersecurity breach, and vice versa. Therefore, a comprehensive ICS security strategy must encompass both physical and cyber security measures.

Challenges in Implementing ICS Security

Legacy Systems and Backward Compatibility

Many ICS systems lack the necessary security features to protect against modern cybersecurity threats. Updating these systems to include robust security measures while maintaining compatibility with existing infrastructure is a significant challenge.

Backward compatibility is essential as replacing entire systems is often not feasible due to high costs and potential disruption to operations. Therefore, security measures must be implemented in a way that does not interfere with the system’s functionality. This balancing act of implementing security measures while ensuring system functionality poses a significant challenge for many organizations.

Network Isolation

Network isolation, or air-gapping, is a common security practice used in Industrial control systems to physically or logically isolate them from external networks, to minimizing exposure to online threats. While effectively reducing the attack surface and unauthorized access, network isolation also hinders ICS security by restricting it ability to deploy client-based security solutions, which rely on communication with remote command-and-control (C&C) servers.

Moreover, systems isolation hinders the timely deployment of new security updates, making them more vulnerable to zero-day vulnerabilities. Monitoring and detecting security incidents in isolated networks become challenging, as mentioned below. In addition, isolated systems may also lack effective data backup and recovery mechanisms.

Real-Time Requirements and Constraints

Many industrial control systems operate in real-time, controlling processes that cannot afford delay or interruption. The constraints of real-time systems limit the types of security measures that can be implemented. For instance, encryption, which is a common practice in IT security, can cause delays in data transmission and thus is often not suitable for ICS. Overcoming these challenges requires innovative solutions and a deep understanding of ICS environments.

Lack of Awareness and Training

Despite the growing threat of cyber-attacks on ICS, there is often a lack of awareness and training among those responsible for these systems. Many ICS operators come from an engineering background, not IT, and may not fully understand the risks and best practices associated with cybersecurity.

In addition, senior management may not recognize the potential impact of a cyberattack on their ICS, leading to a lack of investment in security measures. This lack of awareness and training is slowly changing, but it remains a significant hurdle to implementing effective ICS security.

Organizational and Jurisdictional Challenges

In many organizations, responsibility for ICS security falls between the cracks of IT and engineering departments. This can lead to confusion, lack of ownership, and ineffective security measures.

Jurisdictional challenges arise when dealing with global organizations. Different countries have different regulations and standards for cybersecurity, making it difficult to implement a consistent security strategy across all locations. Navigating these challenges requires clear communication, collaboration, and a comprehensive understanding of international cybersecurity regulations.

5 Best Practices for ICS Cyber Security

1. Perform ICS Asset Discovery

Asset discovery involves identifying all devices, applications, and systems in your ICS and documenting their configurations and vulnerabilities. This process gives you a clear picture of your system’s security landscape and helps you identify potential vulnerabilities.

Asset discovery should be an ongoing process, with regular audits to detect any changes in your systems. It is also important to identify any unauthorized devices connected to your ICS. These could potentially be used as entry points for cyber-attacks.

2. Implement Security Controls

Once you have a clear understanding of your ICS landscape, you can begin implementing security controls. This includes measures such as firewalls, antivirus software, and intrusion detection systems (IDS). These tools help to detect and prevent unauthorized access to your system.

An IDS is especially important, as it monitors your system for any unusual activity, such as attempts to breach your firewall or changes in system configurations. If any suspicious activity is detected, the IDS alerts the system administrator who can then take appropriate action.

3. Perform Network Segmentation

Network segmentation is another important security measure. This involves dividing your network into separate segments, each with its own security controls. Network segmentation helps to contain any potential breaches, preventing them from spreading across your entire network.

For example, you could segment your network based on the sensitivity of the data each segment handles. Highly sensitive data could be stored on a separate, highly secure segment of the network. By limiting access to this segment, you reduce the risk of a breach. Of course, which strategy comes with it’s own set of limitations, already mentioned above.

4. Secure Remote Access

Many ICS are now connected to the internet, allowing for remote monitoring and control. While this brings many benefits, it also introduces new vulnerabilities. To secure remote access, you should implement measures such as two-factor authentication, secure VPNs, and strict access controls.

It’s also crucial to monitor remote access closely. Any unusual activity, such as multiple failed login attempts, should be investigated immediately. Remote access is a common target for cyber attackers, so it’s essential to take these measures to secure it.

5. Employee Training and Awareness Programs

Finally, one of the most effective ways to improve ICS security is through employee training and awareness programs. These programs should educate employees about the risks of cyber-attacks and the importance of security measures.

Training should also provide employees with the skills they need to detect and respond to potential threats. This includes training on recognizing phishing emails, using strong passwords, and reporting any other kind of suspicious activity.

How We Can Help

Industrial systems rely heavily on smart devices, controls and sensors to ensure smooth continuous operations and optimal performance. Each of these devices serves a critical function, and the majority suffer from the above-mentioned security limitations. They are isolated, hard to update, impossible to remotely monitor, exposed to software supply chain vulnerabilities, limited by their age and resource-constrained, and more…

Unsurprisingly, smart devices are often targeted by bad actors using lateral movement tactics to find their way into the system. Still, they continue to be overlooked by security teams, who have learned to accept the security limitation of IoT as a “fact of life.”

The Sternum platform addresses this gap with the introduction of a patented runtime security solution that integrates into the device itself and works on the firmware level to immunize it from all memory and code manipulation attempts. The solution is agentless and connection agnostic, working equally well for connected and isolated devices. Moreover, its deterministic nature ensures protection from zero-day attacks and even supply chain threats in 3rd party code.

Leveraging its on-device presence, the platform also provides continuous monitoring and threat detection features. These enable easy access to live insights, historical data, predictive analytics, incident response and investigation tools, contextual root cause analysis, and more.

In cases where remote connectivity and not available, the information collected by these solutions can be stored on the device itself or transferred over an isolated secure network to a local server.

The solution work with OS and device type, legacy or new, and requires minimal overhead of just 1-3%, causing no interruption to the device’s regular functions.


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