Introduction
In today's digital age, industrial networks form the backbone of modern manufacturing and critical infrastructure systems. However, with the rise of cyber threats, ensuring the security of these networks has become a paramount concern for organisations. One of the most effective strategies to safeguard industrial networks is by implementing network segregation using zones and conduits.
While cyber threats often change, addressing foundational elements such as the network helps reduce the risk of exposure, even if the latest security patches are not applied. Taking an approach of least privilege and least access, we can deliver security practices that are imbedded for the whole lifecycle of the control system.
Understanding Industrial Network Security
Industrial networks consist of interconnected devices, systems, and equipment, which are used to monitor, control, and automate various processes. These networks differ significantly from traditional enterprise networks in terms of scale, complexity, and the potential consequences of a security breach. Any successful cyberattack on an industrial network could lead to severe financial losses, operational disruptions, safety hazards, and even environmental damage.
It is commonplace to have legacy devices in operation that have a plethora of security issues, use protocols that cannot be secured, or have devices that cannot be patched. Replacement is often not an option so how can we look to reduce the risk and reduce our attack surface?
To counter these threats, a robust and multi-layered security approach is required, and that's where IEC 62443 comes into play. IEC 62443, developed by the International Electrotechnical Commission (IEC), is a comprehensive series of standards designed specifically for industrial automation and control systems security.
The Concept of Zones and Conduits
IEC 62443 has the concept of "zones and conduits" as a fundamental principle for enhancing industrial network security. Zones are defined as logical groupings of assets, systems, and components that share similar security requirements and risk levels.
Conduits, on the other hand, act as controlled pathways between zones, regulating data flow and access control between them.
Zones: The Foundation of Segregation
By dividing an industrial network into distinct zones, organisations can ensure that different parts of the network are isolated from one another based on their security needs. This means that even if an attacker manages to breach one zone, the damage will be contained, preventing them from moving laterally throughout the entire network.
Each zone is assigned a security level according to its criticality and vulnerability. Zones with the highest value assets or those exposed to significant risks are allocated the highest security levels and are protected by more stringent measures. Examples of zones in an industrial network may include process control zones, data storage zones, human-machine interface (HMI) zones, and external communication zones.
Conduits: Controlled Communication Paths
Conduits, or security conduits, act as controlled gateways that facilitate communication between different zones in a secure manner. Conduits enforce strict access controls, traffic filtering, and often have deep packet inspection to prevent unauthorised or malicious data from crossing between zones.
The role of conduits is crucial in mitigating the risk of lateral movement within the network. They limit the potential pathways that attackers can exploit and ensure that any communication between zones complies with the organisation's security policies. Conduits can be physical or virtual, depending on the architecture of the industrial network.
It is important to understand the dataflows of your process so that you can only permit the traffic that is authorised to traverse the conduit.
Benefits of Segregated Zones and Conduits
1. Enhanced Security Posture
The primary advantage of using zones and conduits is an improved security posture. By segmenting the network, organisations can protect critical assets and sensitive processes effectively. Even if a security breach occurs, the impact is localised and contained within the compromised zone, preventing the spread of the attack.
2. Reduced Attack Surface
Segmentation significantly reduces the attack surface for potential threats. Since each zone has its own specific purpose, the number of entry points for attackers is limited. This makes it harder for hackers to locate and exploit vulnerabilities across the entire network.
3. Compliance with Industry Standards
IEC 62443 is widely recognised as a global standard for industrial network security. By adopting the principles of zones and conduits, organisations can align their security practices with these international standards, which can lead to easier compliance assessments and certifications. Compliance will also look to reduce insurance premiums too!
4. Simplified Network Management
Contrary to the belief that network segregation complicates management, it actually streamlines the process. Each zone can be independently monitored, maintained, and updated without affecting the other zones. This allows for more efficient troubleshooting and reduces downtime during maintenance activities.
5. Increased Resilience
In the face of cyber threats, industrial networks must be resilient to ensure uninterrupted operations. Zones and conduits provide a way to build redundancy into the system. If one zone becomes unavailable due to an attack or other issues, other zones can continue functioning in ‘island mode’, minimising the impact on overall operations.
6. Micro Segmentation
Segregating your process further to not only address north south traffic but also east west can provide significant benefits. Assessing zones such as authentication with Active Directory, Historical data, Remote Desktop Servers (RDS Servers) and engineering workstations, to mention a few, provides tighter control over the machine-to-machine (M2M) communications ensuring that only traffic that should be part of the process is permitted, all other traffic is denied.
Summary
At SolutionsPT we believe that Industrial network security is a critical aspect of modern-day manufacturing and infrastructure systems. With cyber threats becoming increasingly sophisticated, organisations must take proactive measures to protect their assets and operations. Implementing zones and conduits as defied by IEC 62443 is an essential step in building a robust and resilient cybersecurity posture.
Dividing the network into zones based on security requirements and enforcing controlled communication through conduits can significantly reduce the risk of successful cyberattacks. This approach not only enhances security but also simplifies network management, improves compliance with wider industry standards, and boosts overall resilience in the face of evolving threats.
Embracing the principles of IEC 62443 can be a game-changer for industrial network security in a rapidly digitising world.
