"Attacks on rail systems have increased by 220%." Last August, a retired official from the U.S. National Security Agency (NSA) pointed out that threats to railways have become the spark that ignites warfare in regional conflicts. In recent years, incidents such as train hijackings, railway paralysis, and the cutting off of supply lines have emerged as new national security concerns worldwide. In response, the U.S. National Institute of Standards and Technology (NIST) and the Transportation Security Administration (TSA) jointly issued more stringent rail safety standards in October 2022 to counter these threats and protect critical transportation systems like subways, railways, and train networks.

However, due to the early development of railway and train control systems, many insecure train signaling systems have been widely adopted around the world and have become the mainstream choice for both public transportation and freight operations.

To fully explore the scope of these threats, this session will consolidate and review the six major systems used in global railways and public transportation (e.g., CBTC, ATP, ATC, and PZB) and examine their underlying track signaling control systems. We will begin with a research on ATS (Automatic Train Stop) presented at CODE BLUE 2024—a classic system that has been extensively deployed in Japan and Europe. Its signaling design is intended to automatically stop a train in the event of an emergency, without requiring human intervention. However, once attackers gain sufficient understanding, they can exploit this mechanism to control train operations; even the modern ATC (Automatic Train Control) systems used in North American railways carry similar risks.

The session will cover topics including braking devices, automated signal-based braking, and the communication design and security risks associated with HOTT (Head of Train Telemetry) and EOTT (End of Train Telemetry), along with real-world replay signal attacks. It will conclude with recommendations for preventive measures, aimed at guiding the future development and planning of rail cybersecurity systems to safeguard critical rail infrastructure.