HACKVent 2020 – Day 24

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Challenge – Santa’s Secure Data Storage

In order to prevent the leakage of any flags, Santa decided to instruct his elves to implement a secure data storage, which encrypts all entered data before storing it to disk.

According to the paradigm Always implement your own crypto the elves designed a custom hash function for storing user passwords as well as a custom stream cipher, which is used to encrypt the stored data.…

HACKVent 2020 – Day 23

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Challenge – Those who make backups are cowards!

Santa tried to get an important file back from his old mobile phone backup. Thankfully he left a post-it note on his phone with the PIN. Sadly Rudolph thought the Apple was real and started eating it (there we go again…).…

HACKVent 2020 – Day 22

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Challenge – Padawanlock

A new apprentice Elf heard about “Configuration as Code”. When he had to solve the problem to protected a secret he came up with this “very sophisticated padlock”.


Unpacking the .zip archive, we got a 19MB Linux executable.…

HACKVent 2020 – Day 17

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Challenge – Santa’s Gift Factory Control

Santa has a customized remote control panel for his gift factory at the north pole. Only clients with the following fingerprint seem to be able to connect:


Mission: Connect to Santa’s super-secret control panel and circumvent its access controls.…

HACKVent 2020 – Day 15

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Challenge – Man Commands, Server Lost


Elf4711 has written a cool front end for the linux man pages. Soon after publishing he got pwned. In the meantime he found out the reason and improved his code. So now he is sure it’s unpwnable.Notes…

HACKVent 2020 – Day 14

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Challenge – Santa’s Special GIFt

Today, you got a strange GIFt from Santa:

You are unsure what it is for. You do happen to have some wood lying around, but the tool seems to be made for metal. You notice how it has a rather strange size.…

HACKVent 2020 – Day 10

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Challenge – Be patient with the adjacent

Ever wondered how Santa delivers presents, and knows which groups of friends should be provided with the best gifts? It should be as great or as large as possible! Well, here is one way.…

HACKVent 2020 – Day 9

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Challenge – Santa’s Gingerbread Factory

Here you can customize your absolutely fat-free gingerbread man.

Note: Start your personal instance from the RESOURCES section on top.

Goal / Mission

Besides the gingerbread men, there are other goodies there. Let’s see if you can get the goodie, which is stored in /flag.txt

HACKVent 2020 – Day 8

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Challenge – The game

Let’s play another little game this year. Once again, as every year, I promise it is hardly obfuscated.


The file contained an obfuscated Perl script, neatly formatted to look like tetris. Of couse, when ran, it really was a tetris game.…

HACKVent 2020 – Day 7

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Challenge – Bad morals

One of the elves recently took a programming 101 course. Trying to be helpful, he implemented a program for Santa to generate all the flags for him for this year’s HACKvent 2020. The problem is, he can’t remember how to use the program any more and the link to the documentation just says 404 Not found.…