Network Segmentation for Schools: Limiting Ransomware Spread and Protecting Critical Systems
When ransomware infects a school network, its ability to spread across connected devices determines the scale of the disaster. In schools with flat, unsegmented networks — where all devices, from the headteacher's laptop to the finance server to student Chromebooks, are on the same network — ransomware can propagate across thousands of devices within hours. The Harris Federation's April 2021 attack, which took systems offline across 50 schools, demonstrated the potential scale of ransomware spread in large, interconnected education network environments.
Harris Federation 2021: ransomware spread across networks connecting 50 schools — a segmented network would have limited the blast radius significantly.
Why Flat Networks Are Dangerous in Schools
Many school networks were designed for connectivity rather than security — a flat network where all devices can communicate with each other was simpler to manage and provided the open information-sharing environment that education requires. But flat networks are the ideal environment for ransomware propagation. Once an attacker gains access to any device on the network — through a phishing email, a compromised password, or a vulnerable internet-facing service — they can move laterally to find valuable data and administrative access.
What Network Segmentation Means for Schools
Network segmentation divides the school network into separate zones with controlled communication between them. For a typical school, this means:
- Staff devices: separate VLAN for staff laptops and computers
- Pupil devices: separate VLAN for student devices, isolated from staff systems
- BYOD: separate VLAN for personal devices with internet access only
- Finance and administrative systems: isolated segment with strict access controls
- School MIS server: isolated with access only from authorised staff devices
- Guest WiFi: completely isolated from all school systems
- IoT devices: printers, CCTV, smart boards on a separate isolated segment
Practical Implementation for Schools
Implementing network segmentation requires appropriate network hardware — managed switches and a firewall that supports VLANs. Most modern school networks already have this hardware; segmentation is often a configuration change rather than a capital investment. Schools should work with their IT provider or network manager to design an appropriate segmentation architecture and test it before implementation to ensure it does not disrupt normal operations.
Segmentation as Part of a Layered Defence
Network segmentation alone does not prevent attacks — it limits their impact. It works as part of a layered defence: endpoint protection detects and blocks threats on individual devices; MFA prevents account takeovers that allow lateral movement; email filtering blocks the phishing emails that typically initiate attacks; and network segmentation limits the blast radius if an attacker does gain a foothold. All four layers together provide the proportionate security posture the DfE standards expect.
Frequently Asked Questions
Is network segmentation required by the DfE Cyber Security Standards?
The DfE standards do not explicitly mandate network segmentation, but they require schools to implement proportionate security measures. For schools handling sensitive data — particularly those with large networks or MAT connectivity — network segmentation is considered a proportionate and recommended control by the NCSC. The Cyber Essentials scheme requires boundary firewalls that effectively implement rudimentary segmentation at the network perimeter.
How much does network segmentation cost for a school?
For schools with managed switches and a capable firewall already in place, segmentation may be achievable through configuration changes at low additional cost. Schools with older, unmanaged network hardware may need to upgrade switches — costs vary significantly by school size and network complexity. A managed IT provider or network specialist can assess your current infrastructure and provide a cost estimate for segmentation implementation.
Will network segmentation slow down the school network?
Properly implemented network segmentation should not noticeably affect network performance. Modern managed switches handle VLAN traffic efficiently. The main risk is misconfiguration — creating rules that are too restrictive and breaking legitimate access to school systems. Segmentation should be implemented and tested carefully, with a rollback plan, and introduced during a low-impact period such as school holidays.
Get network security advice for your school
Kyanite Blue specialises in cybersecurity for iGaming operators. MGA-licensed operators across Malta trust our stack.
Get in touchReady to secure your iGaming operation?
MGA-licensed operators across Malta trust Kyanite Blue.