Write-Up Advent of CTF 2020 Challenge 1

Overview

The NOVI University Of Applied Sciences is offering an Advent CTF challenge for December 2020. The CTF is created by our community member of the Hackdewereld.nl and Chief Lecturer for Cyber Security at the NOVI University, Arjen Wiersma. If you want to participate in these CTF challenges, you can create an account on the website https://www.adventofctf.com/.

Challenge 1

• Description: All starts should be easy.
• Points: 100

This challenge has this URL: https://01.adventofctf.com/. So, I visited this URL.

Well, do I have to guess the password? Let’s first check the source code of this website. And, it looks like the one base64 uncoded flag is present in the source code. This looks a lot like challenge 0 🙂

Solution

After decoding this Base64 encoded string, I got the password to log on. So, no password guessing, no Python script creation to password spray, just reading the source code. Sometimes it’s as simple as it seems

~$ echo "YWR2ZW50X29mX2N0Zl9pc19oZXJl" | base64 -d 
advent_of_ctf_is_here

After logging in on the website as Santa, I got the flag.

Thanks for reading!