Keeping defence networks secure as threats evolve

In this article, defence networking expert Rainer Grumann and cybersecurity solutions expert Maciej Goraj explore a challenge for long-lived defence systems: how to keep defence systems secure as threats and technologies evolve. The answer is not frequent replacements, but designing systems that can be re-assessed, protected and selectively upgraded throughout their lifecycle.

Defence systems outlive technology cycles

Defence systems typically remain operational long after the technologies and security requirements around them have changed. But upgrading them is rarely as simple as replacing a piece of equipment. Networking devices are part of larger systems, with interdependencies that can make even individual changes very complex.

The challenge is not simply to build electronic equipment that lasts +20 years. It is to make sure a long service lifeves room for cybersecurity to evolve.

Secure at deployment does not mean secure indefinitely

A system that was state of the art when deployed cannot automatically be assumed to meet the same standard throughout its operational life.

“The system has to be reviewed throughout its life. What was state of the art when it was designed may not be state of the art 5 or 10 years later.” Maciej Goraj, Cybersecurity Solutions Expert

Periodic review provides the visibility needed to decide what comes next. Are the original security assumptions still valid? What new threats, vulnerabilities and weakness emerged? And does it require additional mitigation measures, an update or a more fundamental change?

Assess cybersecurity risks, then choose a proportionate response

Discovering a new risk does not automatically mean replacing the equipment.

Where existing technology can remain in service, a multi-layer cybersecurity approach can help address newly identified threats and weaknesses. Additional security controls such as Next Generation Firewalls, Data Diodes, hardware based crypto devices, network segmentation, device and system hardening or air-gapping are among the measures that can protect components, minimize the cybersecurity attack surface and thus limit the consequences of a potential compromise.

This is particularly relevant for defence systems characterized by long lifecycles, where technologies from different generations may need to coexist. But mitigations have their limits. A periodic risk assessment may eventually show that additional mitigations or software updates are no longer sufficient and that the residual risk cannot be accepted anymore.

Future-proof design for the upgrade you cannot predict

New security requirements may eventually demand capabilities that existing equipment cannot support through software or firmware updates alone.

This calls for a different approach to designing equipment for long-term service. It is not simply about building robust hardware that lasts but considering how components can be updated or selectively replaced when requirements change.

“At some point, software updates may not be enough. You may need more compute power or different hardware components and interfaces required for networking and cyber technologies of the future.” Maciej Goraj, Cybersecurity Solutions Expert

Form-fit-function compatibility can make future replacement less disruptive. In a complex defence system, changing one component can have implications elsewhere.

“There are many interdependencies in a complex defence system. If you can preserve the same form, fit and function when replacing a component, you minimise the repercussions elsewhere.”
Rainer Grumann, Defence Networking Expert

Built to last should not mean built to stand still

No one can design today for every cyber threat or security technology that may emerge over a defence system's lifetime. That is why flexibility and adaptability matters. The aim is not to replace equipment every time requirements change. It is to know when the system needs to be reassessed, when additional protection is sufficient, and when an upgrade has become necessary.

Resiliency and long service life are reasons to plan for security to evolve from the start. Built to last should not mean built to stand still. 

Maciej Goraj Cybersecurity Solutions Expert	Rainer Grumann Defence Networking Expert