In professional cycling, where races can be decided in a matter of seconds, the importance of every aspect of a cyclist’s equipment cannot be overstated. A team of computer scientists recently discovered a critical vulnerability in the wireless gear-shifting systems used in top-level bicycles – a vulnerability that could potentially affect the outcome of high-profile events such as the Tour de France.
A team of researchers from the University of California San Diego and Northeastern University investigated Shimano’s Di2 wireless gear shifting technology, which dominates the bicycle industry. Through a black box analysis, they found three serious vulnerabilities in Shimano’s binary wireless protocol that would allow an attacker to remotely manipulate the gear shifting.
The first vulnerability identified was the lack of mechanisms to defend against replay attacks. If an attacker intercepts and forwards the data, such an attack can take full control of a cyclist’s gearshift without the presence of cryptographic keys. It was shown that such an attack could be carried out using commercially available software-defined radios without signal amplification from a distance of up to 10 meters.
The second problem is targeted locking. An open system locks gear changes on a specific bike while leaving other surrounding systems open. This scenario puts riders at great risk, especially in tightly packed pelotons, as is common in professional racing. Sudden gear changes or complete gear locking can occur, with a possible fall or significant impairment of rider performance.
The third issue involves the leak of information about the ANT+ communication protocol that transmits data between the bike components and the bike computers. This flaw could allow an attacker to monitor a cyclist’s telemetry data in real time, giving an unfair advantage to any competitor who exploits this vulnerability.
These vulnerabilities have significant implications.
In professional cycling, where victory and defeat are often a fine line, a potential remote attack on a competitor’s bike poses a direct threat to the integrity of the sport. The possibility of inadvertent gear changes at high speed, leading to potentially devastating crashes, further underscores the seriousness of these vulnerabilities.
Shimano, the Japanese company behind Di2 wireless shifting technology, has identified the vulnerabilities and is currently working on patches to fix them. The researchers recently presented their findings at the 18th USENIX WOOT Offensive Technologies conference, highlighting the need for cybersecurity measures in modern cycling devices.
As cycling continues to evolve technologically, the security of these systems will be critical to the safety of riders and the integrity of the sport.
