Category: CTF

Ransomware attacks are becoming more common every day. This forensics challenge goes in depth into the solution of the 'Bad Ransomware' challenge of the CSCBE24 Qualifiers dealing with a Known Plain-Text Attack on an encrypted zip archive. We are given a ransomware encrypted file by "connemara" with a slight variation on the magic sequence.

For this years halloween I decided to participate in the Hack The Boo CTF competition from Hack the Box. Despite this being my first solo public CTF competition, I still managed to climb to leaderboards and reach top 50 (48th to be exact). In total I managed to capture 7 out of the 10 flags, some easier than others. In this post I will delve into how I managed to solve the forensics and web challenges, as those where the areas my skills stuck out the most.

Tasked with defending the antidote's research, a diverse group of students united against a relentless cyber onslaught. As codes clashed and defenses were

We are given the following files: Lets see what we are dealing with and list the protections that are enabled: Source code of main and save_msg functions. When we run the program and enter x, we get into the save_msg function that contains both a buffer overflow and format string vulnerability that we can exploit to execute system("/bin/sh") and read the flag on the file system.