Cyber security
Best Practice: Implement network segmentation to isolate critical systems
Sep 12, 2024
Network segmentation is a security practice that divides an organisation’s network into smaller, isolated segments. This approach limits the spread of threats and reduces the risk of unauthorised access to critical systems by isolating them from less secure parts of the network. By compartmentalising the network, organisations can better control access, improve security, and protect sensitive data.
Why Network Segmentation is Important
In a flat, unsegmented network, an attacker who gains access to one part of the network can often move laterally to other systems, potentially reaching critical assets such as databases, payment systems, or intellectual property. By implementing network segmentation, organisations can isolate these sensitive systems, making it harder for attackers to move around within the network.
For example, a payment processing system should not be on the same network segment as employee workstations. If a cyber criminal compromises an employee’s device, network segmentation ensures they cannot easily access payment systems or sensitive customer data.
Key Benefits of Network Segmentation
1. Enhanced Security and Access Control: Network segmentation limits access to sensitive systems, ensuring that only authorised users or devices can interact with them.
2. Reduced Attack Surface: Segmenting the network reduces the pathways an attacker can exploit. Even if they gain access to one segment, their ability to move to other parts of the network is restricted.
3. Improved Containment of Threats: If a malware infection occurs on one network segment, segmentation helps contain the threat, preventing it from spreading to other critical systems.
4. Simplified Compliance: Many compliance frameworks require organisations to isolate sensitive systems, such as payment processing systems under PCI DSS. Network segmentation helps meet these regulatory requirements by restricting access to sensitive data.
Best Practices for Implementing Network Segmentation
- Use VLANs, Firewalls, and VPNs to Segment the Network: Virtual Local Area Networks (VLANs) allow you to divide a network into smaller segments. Firewalls can be used to enforce security policies between these segments, while Virtual Private Networks (VPNs) ensure secure connections to sensitive systems from remote locations.
- Isolate Critical Systems on Separate Segments: Critical assets, such as databases, payment processing systems, and intellectual property, should be placed on separate, highly secured network segments. This prevents unauthorised users from accessing these sensitive areas.
- Implement Access Controls for Each Segment: Ensure that only authorised personnel and devices have access to specific network segments. Use role-based access control (RBAC) and strict firewall rules to manage who can enter each segment.
- Monitor Traffic Between Network Segments: Use intrusion detection systems (IDS) to monitor traffic moving between network segments. This helps identify any suspicious behaviour or unauthorised attempts to access restricted segments.
- Regularly Audit and Update Segmentation Policies: Network segmentation needs to evolve with the organisation. As new systems and processes are added, review and update segmentation policies to ensure that sensitive systems remain isolated and secure.
Conclusion
Network segmentation is an essential practice for reducing the risk of unauthorised access to critical systems and containing potential threats. By using VLANs, firewalls, and VPNs to create isolated network segments, organisations can significantly enhance their security posture, limit the spread of cyber attacks, and ensure compliance with regulatory requirements.
