KringleCon3 2020 Objective One Writeup: Uncover Santa's Gift List


KringleCon3 Overview

KringleCon is the annual Holiday Hacking Challenge put on by the SANS Institute. Players are presented with a variety of security themed objectives and CLI challenges which provide valuable hints. In addition, the KringleCon YouTube Channel provides additional training, helpful for solving obstacles within the game, as well as practical security advice outside the game.

When KringleCon is over, players publish writeups. Each player tackles the objectives in their own unique way. These writeups help us gain insight into the minds of each individual player.

Objective Overview

There is a photo of Santa’s Desk on that billboard with his personal gift list. What gift is Santa planning on getting Josh Wright for the holidays? Talk to Jingle Ringford at the bottom of the mountain for advice.

Objective Detailed Writeup

Initial Findings

When users first enter the game, they are dropped off at the train platform. In the background is a clickable billboard:

Which displays this image:

Assumptions After Initial Observations

  • The swirl effect is a common filter
  • GIMP probably has this filter
  • Using the filter in the opposite direction will unscramble the image.
  • Similar to Unmixing color video I watched a year ago: https://www.youtube.com/watch?v=j2_dJY_mIys

Solving

I approached this problem, by looking for free software with a swirl or twirl distortion effect. GIMP has what I am looking for:

Next, I isolated swirl, trying to keep the center of the swirl in the center of image to make reversing it easier:

Using whirl and pinch filter in GIMP returned the results I needed. This required quite a bit of adjusting the whirl, pinch, and radius settings:

Helpful Advice

Carefully read the objective and the hints. After spending way too much time searching for tools with a swirl filter and learning how to use GIMP, I determined one of the elves suggested a online image editor that would have made the objective much easier.

Talk to the elves, they have valuable information. Once objective one was complete, I walked around the entire board talking with each of the elves.

Answer

Josh Wright wants a Proxmarx for Christmas.

Note, I didn’t read the directions closely enough and spent way too long trying to recover all the names:

  • Ed - Two Front Teeth
  • Unknown - OU Jersey
  • Jeremy - Blanket
  • Brian - Lei | Lci
  • Josh Wright - Proxmark
  • Clay - Darthvader Suit
  • Tad - Holiday Lights
  • Phil - Stuffed Pikachu
  • Jerry - Trip to North Pole