Safety and Security Division

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IACS Network Security Strategies

By Durgesh Kalya posted 25 Jan, 2023 08:51 PM


Network security is one of the main pillars of defense-in-depth strategies in Industrial Control Systems and Business enterprise systems. Network security refers to the measures taken to protect the integrity and accessibility of networked systems and data.
Network Security can include implementing firewalls, encrypting communications, and regularly updating software to fix vulnerabilities.

There are several types of network security strategies, including:

Preventative: These strategies aim to prevent security breaches from occurring in the first place, such as by implementing firewalls and intrusion prevention systems.

Detective: These strategies are designed to detect security breaches that have already occurred, such as by using intrusion detection systems and security information and event management (SIEM) software.

Corrective: These strategies are implemented after a security breach has occurred in order to contain the damage and recover from the incident, such as by implementing incident response plans and disaster recovery procedures.

Recovery: These strategies are implemented after a security breach has occurred in order to restore normal operations and recover data, such as by implementing backup and disaster recovery procedures.

Deterrent: These strategies are implemented to discourage potential attackers, such as by implementing security policies and procedures, security awareness training, and security certifications.

Compensating controls: These strategies are implemented to reduce risk in the event of a security breach, such as by implementing security controls at multiple layers of the network or implementing physical security controls to protect data centers.

It is important to note that different network security strategies are not mutually exclusive and can be combined to provide a robust defense against security threats.

Implementing Network Security in OT (ICS) Environments

Network security in operational technology (OT) or industrial control systems (ICS) environments is implemented through a combination of technical and non-technical measures. Some key practices include:

Segmentation: Segmenting the OT network from the IT network can help to reduce the risk of cyber attacks spreading from the IT network to the OT network.

Access control: Implementing strict access controls can help to prevent unauthorized access to OT systems and data, such as by using secure authentication methods and role-based access controls.

Patch management: Keeping OT systems up-to-date with the latest security patches and software updates can help to protect against known vulnerabilities.

Monitoring and logging: Regularly monitoring and logging the OT network activity can help detect and respond to potential security threats, such as by using intrusion detection systems and security information and event management (SIEM) software.

Incident response: Developing and regularly testing incident response plans can help to quickly and effectively respond to security breaches and minimize the damage caused by an attack.

Physical security: Implementing physical security controls, such as security cameras and access controls, can help to protect against tampering or unauthorized access to the facilities where OT systems are located.

Cybersecurity awareness training: providing training to the personnel who operate and maintain the OT systems can raise awareness of potential security risks and encourage safe and secure practices.

Regular risk assessment: Regularly assessing and evaluating the risks to the OT systems and the environment in which they operate can help to identify potential vulnerabilities and prioritize security measures.

The OT and ICS environments have different characteristics than IT, such as real-time requirements, safety-critical systems, and long life-cycle equipment, so the security measures need to be tailored for the specific environment.

Network segmentation in industrial control networks (ICNs) divides a single network into multiple smaller networks or segments to reduce the potential attack surface and limit the spread of any security breaches.

Segmenting the ICN makes it much harder for an attacker to move laterally through the network and gain access to sensitive assets. This is accomplished by using network devices such as firewalls, routers, and switches to create separate logical or physical segments for different types of devices or systems.

For example, one segment may contain only critical control systems. In contrast, another segment may contain only non-critical systems or IT systems that are not directly connected to the control systems. By isolating the critical systems from the non-critical systems, the risk of a security breach impacting the critical systems is significantly reduced.

Different types of segmentation can be used depending on the specific requirements and characteristics of the ICN.

Some of them are:

Physical segmentation: physically isolating the networks using firewalls, routers, and switches.
Logical segmentation: isolating the networks using virtual LANs (VLANs) or virtual private networks (VPNs).
Micro-segmentation: dividing the network into smaller segments, each with its own set of security policies and access controls.

It is important to note that network segmentation alone cannot provide complete security; it should be combined with other security measures such as access control, monitoring, incident response, and regular vulnerability assessments to provide a comprehensive security solution.

Cartoon Credit: Siddhant Kalya