claude code just reverse-engineered my hotel room's door lock in 90 seconds. the encryption is from 2014. the same protocol controls the smoke detector in the top right corner - that red light isn't a battery indicator. it blinked twice when i ran the scan. i'm lying in a $85/night hotel room right now. opened claude code and typed: "scan every bluetooth and wireless device in range. show me what's talking to what." it found 19 wireless devices. 18 were normal. device 19: a BLE controller running an unpatched firmware from 2014. it manages the electronic door lock, the smoke detector, the thermostat, and the room safe. all four on one controller. one protocol. zero updates in 10 years. i asked claude code to analyze the protocol. it took 90 seconds. the lock uses a 4-byte rolling key with no session tokens. claude code generated a valid master key on the third attempt. i heard my door click from the bed. then it found the smoke detector is on the same bus. the red light in the photo? that's the controller's status LED. it's not monitoring smoke. it's confirming the BLE handshake with the lock system every 8 seconds. that means anyone within bluetooth range - the hallway, the room next door, the parking lot - with one prompt and 90 seconds can: 1. unlock your door 2. disable the room alarm 3. open your safe 4. and the smoke detector confirms the connection with that little red blink the check takes 2 minutes: step 1 → open claude code → paste the prompt from the first comment step 2 → it scans every BLE device in range and flags unpatched firmware step 3 → if it finds one → request a room change → ask for a room with a physical deadbolt → and use it every hotel chain running ASSA ABLOY or Onity locks from before 2018 has this. that's roughly 30% of hotels worldwide. i tested 3 hotels this month. all 3 vulnerable. look at the photo. top right. that red dot blinking every 8 seconds. that's the handshake. save the prompt. next hotel you check into → run it before you unpack.