• Stopping the apocalypse part 1
  • easy

As you wake up, the first thing you notice is a headache. The second one is that you are in the back of a vehicle you do not remember entering. You hear unfamiliar voices outside. Something about an “important device” and “the apocalypse”. While it sounds fairly interesting, you can’t make out the details.

Sitting up, you notice something on your legs. No one seems to be around, so You are free to take a closer look. It looks like a fancy cuff. On the device, You notice what appears to be a connector, labeled UART…


Note: If you believe to have successfully connected, but receive no feedback from the device, you might want to ask it to help you.

author: Wintermute, Csf3r3ncz1


Simply the most annoying HW challenge, at least for me. We were given a fake linux shell user@banana-tau (obvious Raspberry Pi reference), and had to “connect” to a serial device using UART.

You know what I did not notice the first 5 or so times when I’ve attempted this? A button on the upper-right corner where I can “connect” the wires. Who might have guessed that this works best when plugged in?

Anyways, connecting UART is easy: RX to TX and vica versa (as you want to receive what the other transmits, and also the other way around). Also GND goes to GND.

A few commands actually worked on the terminal, namely ls /bin/ told us we have id (useless), ls (mostly useless), lsusb and ttycon.

lsusb tells us there’s an USB-UART converter connected and it’s available at /dev/ttyUSB0 (could have guessed that as I’ve used those things before).

ttycon asks for a device and also some parameters, namely baudrate, databits, parity bit and stopbits.

Guessing them is a bit boring, but fortunately it was mostly the normal stuff (8 data bits, 1 stop bit, no parity) and the baud rate was 115200, witch is a common one.

Command: ttycon -baud-rate 115200 -data-bits 8 -parity-bit none -stop-bits 1 /dev/ttyUSB0

After that, typing help told me that:

available commands: check-updates, factory-reset, help, system-info

Trying all of them resulted in factory-reset printing the flag, and also unlocking the chains on my leg…