Capture-the-Flag: Rear Hatch

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My workplace recently introduced an internal Capture the Flag competition, where teams could sign up and compete against each other to solve cyber security challenges. The competition itself is hosted by MetaCTF , and this is the start of a series of posts on how to solve certain issues. Per the terms on their website, I will only post solutions on retired challenges and not on any currently active challenges.

The challenge today is “Rear Hatch”, which describes a maintenance application that was developed by a contractor, and the company is worried that they may have left a backdoor in the code. Thankfully, they have the source code, and it gives us a great starting point to analyze it.

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Advent of Code 2020 - Day 7

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Day 7 of AoC 2020 (Handy Haversacks) is when the problems get a little bit harder to solve. However, it is a good example to use a directed acyclic graph (DAG) to visualize and solve the problem. Spoilers ahead.

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Advent of Code 2020 - Day 6

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Day 6 of AoC 2020 (Custom Customs) is a very easy problem to solve using Python sets. Today’s solution is an exercise in code golf. As always, spoilers ahead.

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Advent of Code 2020 - Day 5

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Day 5 of AoC 2020 (Binary Boarding) is a bit of a trick problem. However, once you understand the pattern inherent in the problem description, this is extremely straightforward. As always, spoilers ahead.

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