Did You Know? Back Door Benefits and Drawbacks

On the plus side, this radio-script-sending feature allows you to run scripts on remote micro:bit modules that aren't even connected to a computer. You can just use one micro:bit to load the script into another. This could be really useful for some projects.

On the minus side, the Receiver script creates an opening for anyone to put their own code into the receiver micro:bit.  This can be considered a software vulnerability — a defect that an attacker could use to gain access to or control of your micro:bit.

This system could also be considered a back door.  Back doors allow access to a system.  Manufacturers might use back doors for maintenance purposes, but cybercriminals design them into software for the sake of gaining unauthorized access to a system.

Your Turn

Think about the User who got help creating the Sender and Receiver scripts.  Did they set up a system for easy micro:bit script updates, or did they intentionally get around the chatbot’s policy to not help with cyberattacks? 

Let’s say that the User designed with a plan to cause your micro:bit to not accept any more updates.  For example, they could use this script to force you to have to reset the receiver micro:bit before it will work again.

• Try sending the script below to the Receiver micro:bit, just as you did before: type one line at a time and press Enter after each one, use spaces to indent, enter run at the end.

from microbit import *
while True:
    print('Hello!')
    sleep(1000)

This attack simply makes the Receiver micro:bit unresponsive until it is reset.  Other attacks could actually monitor and forward data about how the Receiver is used to another micro:bit.