Understanding networks segregation as an information security control in ISO/IEC 27001:2022

Network security is a critical component of the information security management system (ISMS) in many organizations. 

One of the controls in ISO/IEC 27001:2022 that refer to networks security is titled Segregation of networks, and its correct understanding and implementation are important for enhancing network security and for minimizing the risks associated with data breaches and cyberattacks. In this article, we delve into what this control entails, explore why and how network segregation should be implemented and discuss the challenges and best practices associated with it.

Segregation of networks in ISO/IEC 27001:2022

ISO/IEC 27001, the international standard that defines the requirements for an information security management system, includes a range of security controls designed to protect the confidentiality, integrity and availability of the information processed by an organization. Those controls are divided into 4 themes – Organizational controls, People controls, Physical controls and Technological controls. 

The control that refers to networks segregation is one of the technological controls and it says that “Groups of information services, users and information systems shall be segregated in the organization’s networks.”

In other words, the standard says that the organization should consider dividing its network into smaller, isolated segments, each with its own security controls, to prevent unauthorized access and to reduce the impact of potential security breaches.

Why implement network segregation?

Network segregation offers several key benefits including:

Enhanced security - by isolating sensitive information and critical systems, network segregation reduces the risk of unauthorized access and limits the potential damage of a cyberattack.

Improved performance, as segmented networks can optimize performance by reducing congestion and improving traffic flow.

Easier management - segregated networks are often easier to manage, monitor, and troubleshoot.

Implementing network segregation

Network segregation can be implemented in various ways, depending on the type of network and on the organization's specific needs. 

1. Physical segregation

Physical segregation involves using separate hardware for different network segments. This method provides the highest level of security, but the downside is that it can be expensive and difficult to manage. It is often used in highly secure environments such as government agencies and financial institutions.

2. Virtual local area networks (VLANs)

VLANs allow logical segmentation of a network into different broadcast domains without requiring separate physical hardware. VLANs are a cost-effective way to implement network segregation and can be easily managed using network switches. They are widely used in enterprise networks to isolate different departments or user groups.

3. Network access control (NAC)

NAC solutions can enforce policies for device authentication and network access, ensuring that only authorized devices can connect to specific network segments. This approach is particularly useful for managing the security of wireless networks and guest access.

4. Firewalls and subnetting

Firewalls and subnetting can be used to create secure zones within a network and controlling traffic flow between different segments. Firewalls can enforce security policies and monitor traffic, while subnetting helps in organizing the network and minimizing broadcast traffic.

Wireless network segregation

Implementing network segregation in wireless networks presents unique challenges generally due to the poorly defined network perimeter and the nature of wireless communication. Here are some strategies for implementing networks segregation for wireless networks:

Separate SSIDs. Use different SSIDs for different user groups or devices. For example, one SSID for employees and another for guests.

Wireless VLANs. Combine VLANs with wireless networks to segregate traffic. Modern wireless access points and controllers support VLAN tagging.

Advanced encryption. Use strong encryption methods like WPA3 to ensure that data transmitted over the wireless network is secure.

Access control lists (ACLs). Implement ACLs to restrict access to specific network resources based on the SSID.

Challenges and best practices

Challenges

Complexity: network segregation can introduce complexity in network management and troubleshooting.

Cost: physical segregation and advanced NAC solutions can be costly to implement and maintain.

User experience: poorly implemented segregation can impact user experience, causing frustration and reduced productivity.

Best Practices

Plan thoroughly. Carefully plan the network design, considering the organization's security requirements and potential risks.

Use automation. Leverage automation tools to manage network configurations and enforce security policies consistently.

Regular monitoring. Continuously monitor network traffic and access patterns to detect anomalies and potential security threats.

Employee training. Educate employees about the importance of network security and best practices for accessing network resources.

Conclusion

By implementing effective segregation strategies, organizations can protect sensitive data, improve network performance and comply with the requirements of ISO/IEC 27001:2022. While challenges exist, following best practices and leveraging modern technologies can help organizations achieve robust and efficient network segregation.

By understanding the importance and implementation of network segregation, organizations can build a resilient network infrastructure that safeguards their valuable information assets.

The segregation of networks is only one of the 93 security controls in ISO/IEC 27001:2022. If you are interested in a detailed presentation of the requirements for an ISMS (Information Security Management System) you can check out our course on Udemy. For guidelines on how the security controls can be implemented we have a different standard (ISO/IEC 27002:2022) and a different course available here.

You can check out all our courses here.

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