Gman CTF Writeups

HHC 2025

2 min read

SANS Holiday Hack Challenge 2025 - Revenge of the Gnome(s)

The Dosis Neighborhood map

The Holiday Hack Challenge (HHC) has been around for 22 years! But this year marks a particularly interesting milestone: 10 years ago, in 2015, HHC introduced an in-game world for the first time. To mark this 10th anniversary, HHC 2025 is the sequel of the story that began back then. In 2015, the story was titled Gnome in Your Home. The gnomes were actually IoT devices with cameras hidden in their eyes, sending images to crowdsource burglars who were planning to steal everything on Christmas Eve. Luckily, an army of cybersecurity professionals foiled the plan and Christmas was saved.

Now, in 2025, those gnomes have come to life! We need to uncover what’s their nefarious plan, who is behind it all, and save Christmas once again!

This is me, GmanH4ck3r, and I joined the cybersecurity professionals with the mission of saving 2025’s Christmas!

Challenge Write-Ups

The solutions for each challenge are organized under their corresponding Act. Each challenge write-up follows the following structure:

  • Header: Difficulty, link to the NPC who provided the challenge, map location, and the challenge URL or file link.
  • Helpful references: When provided, it contains links to background material that can provide help on how to solve the challenge. Some references are provided by the challenge itself, while others come from my own research to help people that would like to solve the challenge while avoiding reading the full solution.
  • Solution: Main write up describing how the challenge was solved.
  • Summary: Some solutions include a summary section with the commands strictly needed to complete the challenge without any additional explanation.
  • Extras: Alternative solutions or technical curiosities that I did not consider an Easter egg or not big enough to deserve a dedicated section.

Extras

This section contains Easter eggs and other fun aspects about the HHC2025 world, as well as alternative solutions or curiosities that deserved a section of their own.

NPCs

This section contains all NPCs in the game (with a dialogue), including their dialogue, map location, and the challenges they provide.

5 items under this folder.