[SpookyCTF'24] encryption-activated
encryption-activated encryption-activated 452 medium 133 solves As weird as this may sound, RB seems to have decrypted some of Simon Letti's important document. Can figure out how to encrypt Simon's file to get recover the document? Developed By: TomB Files:
encrypt.py flag.output This was a slightly confusing crypto challenge that wrecked my pea-sized brain (to be fair, I misunderstood the encryption script for a good 1/2 hour).
The Challenge We are given a Python file that is slightly complicated:
[DuCTF'24] - Sniffy
Sniffy This challenge consisted of a path traversal vulnerability and something similar to a MIME type confusion attack. While I was not able to solve this during the CTF due to a skill issue, I decided to attempt to solve it after the CTF in hopes of being able to better understand what’s going on.
Description Visit our sanctuary to hear the sounds of the Kookaburras!
The source code for the challenge can be obtained from here.
[TJCtf'24] Pals
Pals This was a pretty interesting PNG forensics challenge that pertained to the concept of PNG-specific steganography utilising the PLTE chunk, or the palette chunk. The challenge provided us with a PNG image, pals.png.
The image file can be downloaded here.
The Initial Analysis Given any image forensics challenge, the first step I would take would be to dump it into Aperi’Solve. Aperi’Solve is a pretty powerful tool that runs a bunch of image forensics tools/scripts on the image like strings, binwalk, exiftool, stegsolve, etc. It’s a great tool to get quick indicators of what to look for.
[Cyber Apoc '24] Dynastic
Dynastic This was a crypto challenge where we are given a Python script (encryption algo) and the output text file (cipher). The given files can be found here.
Description You find yourself trapped inside a sealed gas chamber, and suddenly, the air is pierced by the sound of a distorted voice played through a pre-recorded tape. Through this eerie transmission, you discover that within the next 15 minutes, this very chamber will be inundated with lethal hydrogen cyanide. As the tape’s message concludes, a sudden mechanical whirring fills the chamber, followed by the ominous ticking of a clock. You realise that each beat is one step closer to death. Darkness envelops you, your right hand restrained by handcuffs, and the exit door is locked. Your situation deteriorates as you realise that both the door and the handcuffs demand the same passcode to unlock. Panic is a luxury you cannot afford; swift action is imperative. As you explore your surroundings, your trembling fingers encounter a torch. Instantly, upon flipping the switch, the chamber is bathed in a dim glow, unveiling cryptic letters etched into the walls and a disturbing image of a Roman emperor drawn in blood. Decrypting the letters will provide you the key required to unlock the locks. Use the torch wisely as its battery is almost drained out!
[Cyber Apoc '24] Urgent
Urgent This was an email forensics challenge where we are given an EML message file and are required to extract the flag from it. The given file can be found here.
Description In the midst of Cybercity’s “Fray,” a phishing attack targets its factions, sparking chaos. As they decode the email, cyber sleuths race to trace its source, under a tight deadline. Their mission: unmask the attacker and restore order to the city. In the neon-lit streets, the battle for cyber justice unfolds, determining the factions’ destiny.