Daniel Bernegger

HACKVent 2020 – Day 21

Challenge – Threatened Cat

You can feed this cat with many different things, but only a certain kind of file can endanger the cat.

Do you find that kind of files? And if yes, can you use it to disclose the flag?…

HACKVent 2020 – Day 19

Challenge – Docker Linter Service

Docker Linter is a useful web application ensuring that your Docker-related files follow best practices. Unfortunately, there’s a security issue in there…


This challenge requires a reverse shell. You can use the provided Web Shell or the VPN to solve this challenge (see RESOURCES on top).…

HACKVent 2020 – Day 18

Challenge – Santa’s lost home

Santa has forgotten his password and can no longer access his data. While trying to read the hard disk from another computer he also destroyed an important file. To avoid further damage he made a backup of his home partition.…

HACKVent 2020 – Day 16

Challenge – Naughty Rudolph

Santa loves to keep his personal secrets on a little toy cube he got from a kid called Bread. Turns out that was not a very good idea. Last night Rudolph got hold of it and frubl’d it about five times before spitting it out.…

HACKVent 2020 – Day 12

Challenge – Wiener waltz

During their yearly season opening party our super-smart elves developed an improved usage of the well known RSA crypto algorithm. Under the “Green IT” initiative they decided to save computing horsepower (or rather reindeer power?) on their side.…

HACKVent 2020 – Day 11

Challenge – Chris’mas carol

Since yesterday’s challenge seems to have been a bit on the hard side, we’re adding a small musical innuendo to relax.

My friend Chris from Florida sent me this score. Enjoy! Is this what you call postmodern?…

HACKVent 2020 – Day 6

Challenge – Twelve steps of christmas

On the sixth day of Christmas my true love sent to me…

six valid QRs,
five potential scrambles,
four orientation bottom and right,
and the rest has been said previously.

PDF version


a printer




Since I am not that much into rubik cubes, I tried the brute force method.…

HACKVent 2020 – Day 5

Challenge – Image DNA

Santa has thousands of Christmas balls in stock. They all look the same, but he can still tell them apart. Can you see the difference?


The first attempt so solving the challenge was to load the images into an editor and inspect them visually.…