For this challenge we are given the following image and asked to find a flag with the format flag{something_here}: Since is a scripting challenge, let’s start parsing the image. import cv2 import...

tooeasy is a reversing challenge with 17 solves. The description reads: I mean lets get to basics, I have my tried to get in how real malware authors would hide there stuff but still this chall ...

Recently I published a blog post on libbus, a small library I wrote to handle distributed message passing between threads. The library makes use of atomic functions to ensure synchronism. These ope...

Earlier this week I wrote, over the course of an evening, a very simple library to implement basic shared message passing called libbus. In this blog post I want to delve a bit deeper into the rati...

In this stego challenge we are given a password protected zip called turtles128.zip. After bruteforcing it we observe that there are 128 nested zips protected with “0” or “1” as their password. We ...

Hacker Manifesto is a 250 point reverse engineering challenge. It reads: We found this file on a compromised host. It appears to contain data, but we’re not sure how to decode it. Maybe you can ...

In this web challenge we have a short PHP code where it is possible to execute arbitrary code after bypassing two input sanitization filters. First, we have an input length limitation protection...

Time to Draw is a web challenge based on Node.js. The main page presented a canvas on which one could draw by clicking on it, and several buttons on the right side. One of those buttons showed the ...

EXCELlent is a medium difficulty challenge that got 58 solves. It reads: Excellent CTFs need excellent business strategies, and what would be more appropriate than Microsoft ® Excel ™? Of course...

In this challenge our goal is to decrypt the flag using a binary called 8_of_hearts.elf. Looking at this binary we see that there is an encryption routine where each byte is decoded with an XOR ope...