The keyfob subsystem in Honda vehicles allows a replay attack for unlocking, related to a non-expiring rolling code and counter resynchronization. This issue is connected to the system of keyless access in modern vehicles, based on rolling codes generated by a pseudorandom number generator algorithm to ensure the use of unique strings at each button press. A counter in the vehicles checks the chronology of generated codes, increasing the counter upon receiving a new code. However, researchers found that the counter in Honda vehicles resynchronizes when the vehicle receives consecutive lock/unlock commands, causing the vehicle to accept codes from a previous session that should have been deemed invalid. An attacker equipped with software-defined radio equipment can intercept a sequence of codes and replay them later to unlock the vehicle and start its engine.