In the standard, Service $27 was meant to prevent unauthorized tuning. But in the modified version used by the city’s fleet, a specific sequence of "Request Seed" and "Send Key" messages created a buffer overflow. It wasn't a bug; it was a backdoor. Someone had built a secret entrance into every vehicle on the road, hidden inside the most boring document imaginable.
: Validate that different vehicle components communicate diagnostic data correctly over the CAN bus. iso 142293 pdf