In the 21st century, trains have evolved far beyond steel and track gauge. Modern rolling stock increasingly incorporates one or more IP networks that are growing ever more complex. Connected passengers, smart sensors, and critical operating systems now converge within the same environment, sharing physical cabling and radio spectrum. This digital transformation has delivered greater efficiency and new capabilities, but it has also introduced cyber threats that can compromise operational safety in a railway cybersecurity environment.
The new paradigm: harmonizing safety and speed
In the railway sector, the traditional mantra of “safety first” must be reinterpreted for the digital age. It is no longer enough to be secure; we must also be fast. Effective cybersecurity in embedded networks requires detecting threats, making decisions, and deploying countermeasures before an attacker can complete their chain of techniques, tactics, and procedures (TTP). This race against time ultimately determines the success or failure of any defensive strategy.
Deciphering the pyramid of pain
Modern railway cybersecurity architectures face what we refer to as the “pyramid of pain”: multiple layers of complexity that slow down incident response. Overcoming this challenge requires translating each layer of that pyramid into practical, actionable controls within embedded networks.
The strategy begins with smart segmentation and multi-layered policies operating at the L3, L4, and L7 levels of the OSI model. The goal is not merely to separate networks, but to establish logical boundaries that restrict the lateral movement of potential attackers. Deep SSL packet inspection allows encrypted traffic to be decrypted without compromising privacy, while combined IT/OT signatures detect both traditional corporate threats and vectors specific to operational technology.
This defensive framework is completed by IDS/IPS capabilities integrated into next-generation firewalls (NGFW) specifically designed for critical infrastructures. These solutions provide intrusion detection and active prevention tailored to the unique demands of the railway environment.
From flow mapping to dynamic behavior
The key lies in smart observation. By passively listening to network traffic, we can establish a profile of each train’s normal operational behavior: how passengers interact with onboard entertainment systems, which protocols are used by passenger information systems (PIS), how CCTV cameras communicate with storage servers, and what patterns characterize onboard control systems.
This behavioral baseline enables the deployment of dynamic policies capable of intercepting anomalous traffic in real time, without degrading the user experience or disrupting train operations. The goal is not only to block known threats, but also to detect deviations from expected behavior that may indicate sophisticated attacks or zero-day vulnerabilities.
Resilience in the face of the unknown
Zero-day attacks represent one of the greatest challenges in cybersecurity, as they exploit vulnerabilities for which no signatures or patches yet exist. Defending against these threats requires a combination of advanced analytics and intelligent orchestration at the network edge.
Critical embedded systems—such as PIS, CCTV, traction control, and braking systems—must be shielded by architectures that assume the existence of unknown threats. This approach involves implementing compensating controls, including microsegmentation, application whitelisting, continuous integrity monitoring, and sandboxing capabilities that can isolate suspicious components without impacting overall operations.
A minimalist playbook for operators
Complexity is the enemy of security. Railway operators need a clear action manual that prioritizes what truly matters:
1. Critical telemetry: Identify the metrics that are genuinely useful for detection purposes. Rather than collecting everything, monitoring should focus on meaningful indicators such as connections to unusual destinations, changes in bandwidth consumption patterns, attempts to access restricted network areas, and anomalies in industrial protocol behavior.
2. Automated thresholds: Establish triggers that initiate immediate responses without human intervention. If an embedded system attempts to communicate with an unauthorized IP address, the response must be instantaneous: block, isolate, and alert.
3. Quick update adoption: Accelerate the secure deployment of new software versions and protocols without disrupting commercial operations. This requires test environments that mirror production configurations, along with instant rollback mechanisms to handle unexpected behavior.
Reducing surface area, increasing visibility
The implementation of logical boundaries significantly reduces the attack surface while dramatically increasing operational visibility . The result is fewer entry points for attackers and more sensors monitoring every segment of the embedded network.
Above all, time is the decisive factor. Achieving a response cycle that matches or outpaces the attacker’s own cycle is critical. When threats are detected, analyzed, and neutralized faster than the attacker can strike, we win.
Conclusion: a single operational requirement for railway Cybersecurity
In railway cybersecurity, “secure” and “fast” are no longer opposing concepts or separate objectives. They are two sides of the same coin—inseparable attributes of a single operational requirement. Modern trains are moving digital platforms and protecting them demands defense systems capable of operating at the speed of the data they carry.
The question is no longer whether we can afford to invest in advanced cybersecurity for onboard networks, but whether we can afford not to. In this new landscape, an offline train is safer than a poorly protected one.
At Teldat, we pride ourselves on our expertise in advanced cybersecurity for onboard networks, delivering a comprehensive portfolio of cybersecurity and communications solutions for a wide range of railway environments.
