Hacking the Fob
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I Tried the Honda Key Fob Hack on My Own Car. It Totally Worked
Hackers have uncovered ways to unlock and start nearly all modern Honda-branded vehicles by wirelessly stealing codes from an owner's key fob. Dubbed "Rolling Pwn," the attack allows any individual to "eavesdrop" on a remote key fob from nearly 100 feet away and reuse them later to unlock or start a vehicle in the future without owner's knowledge.
Despite Honda's dispute that the technology in its key fobs "would not allow the vulnerability," The Drive has independently confirmed the validity of the attack with its own demonstration.
Older vehicles used static codes for keyless entry. These static codes are inherently vulnerable, as any individual can capture and replay them at will to lock and unlock a vehicle. Manufacturers later introduced rolling codes to improve vehicle security. Rolling codes work by using a Pseudorandom Number Generator (PRNG). When a lock or unlock button is pressed on a paired key fob, the fob sends a unique code wirelessly to the vehicle encapsulated within the message. The vehicle then checks the code sent to it against its internal database of valid PRNG-generated codes, and if the code is valid, the car grants the request to lock, unlock, or start the vehicle.
The database contains several allowed codes, as a key fob may not be in range of a vehicle when a button is pressed and may transmit a different code than what the vehicle is expecting to be next chronologically. This series of codes is also known as a "window," When a vehicle receives a newer code, it typically invalidates all previous codes to protect against replay attacks.
This attack works by eavesdropping on a paired keyfob and capturing several codes sent by the fob. The attacker can later replay a sequence of valid codes and re-sync the PRNG. This allows the attacker to re-use older codes that would normally be invalid, even months after the codes have been captured.
