David Sopas – Web Security Researcher

October 17, 2018 at 4:48 pm

Opening a fingerprint + BLE smartlock – the smart way!

I got my hands on a smartlock that costs around 35€ on Amazon which unlocks using the fingerprint or app (using BLE).
In reality I don’t know the brand and model but this is not something that I really care. What I wanted to check was – how hard was breaking this smartlock?

After a quick inspection I noticed that this lock had something covered below the USB port (which is used to power the battery). Using a sharp knife I scrubbed the thing up and… a screw appeared 🙂

C’mon… Really? I opened it and start disassembling the device.

I needed to scrub also some parts because this lock was supposed to be waterproof so they covered some wires.

In the end, we got a small PCB with a connected fingerprint sensor. Didn’t saw any spring like other locks and can’t manage to open it by shimming. But I saw a motor which was connected by a white and yellow wire to the PCB.

I already played with some motors and other devices like that on Arduino and they usually only need some power to rotate. In this case, I’m guessing that connecting the 3.7V battery to the PCB wires it will rotate (or open).

I grabbed a couple of wires to prevent soldering or damaging the lock and connected them to the lock battery. Than connected the wires to the PCB part that connected to the motor.

And the lock opened. No fingerprint or BLE needed.

Check out the small video that I did – https://www.youtube.com/watch?v=VEjwV3LsLJ0

So I guess you take around 5 second to open this lock using a direct connection to the motor.
The vendor claims its a strong lock… Anyone can break it in 5 seconds.

Screwdrivers rule! 🙂

Hardware , IoT # , , ,
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