Objective: Thaw Frost Tower’s Entrance

Turn up the heat to defrost the entrance to Frost Tower. Click on the Items tab in your badge to find a link to the Wifi Dongle’s CLI interface. Talk to Greasy Gopherguts outside the tower for tips.

By running iwconfig, it showed the current settings for the WiFi dongle (it wasn’t connected to anything) and it had one card: wlan0.

Once the device was in range, though, with the same network as the thermostat, I could see nearby networks available via iwlist.

Initial commands

To connect the dongle to the network, I simply ran iwconfig and specified the dongle’s WiFi card and the target ESSID (Extended Service Set Identification).

Connecting to the network

Then, once on the network, I used curl to interact with the thermostat’s API. The base page provided documentation on the available endpoints and syntax.

Connecting to the API

API docs

The only endpoint we have access to without credentials is the api/cooler which appears to have a temperature setting we can adjust.

API endpoints

Simply setting the temperature to above freezing (above 0 deg. C) got the door unfrozen!

Changing the temperature

To see my other writeups for this CTF, check out the tag #kringlecon-2021.

References