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Recent writeups


Integral Communication

01/11/2024

Stephen does some crypto problems, featuring AES CBC Bit Flipping!


armbox

12/03/2023

We don't have enough compute to run full system emulation for seccomp D: You'll have to make do with this budget seccomp implementation.


hopscotch

12/03/2023

These one byte write challenges have been all the rage recently, so I decided to write one too!These one byte write challenges have been all the rage recently, so I decided to write one too!


ret2thumb

12/03/2023

I can't figure out the difference between ARM and Thumb...


flag-sharing

10/08/2023

cache side channel


misc/geoguessr

08/14/2023

careful when you post photos kids.


ELFcrafting-v1

07/18/2023


ELFcrafting-v2

07/18/2023


frog-math

07/18/2023


i-love-ffi

07/18/2023

I love ffi, don't you?


perfect-sandbox

07/18/2023


permissions

07/18/2023

Every programmer should read the Intel Software Developer Manuals at least once.


simple-heap-v1

07/18/2023


simpleOS

07/18/2023


Fancy Page

06/21/2023

Simple tasks need fancy solutions, change my mind!


Packet Hero

06/21/2023

I love when they open random program and dump pcap for ctf chall.


Vulpes Vulpes

06/21/2023

Fox fox fox fox fox fox.


gaga

05/04/2023

Easy beginner pwn


leek

05/04/2023

No leaks here...


queue

05/04/2023

I just learned about stacks and queues in DSA!


Sailor's Revenge

05/04/2023

First blockchain pwn!


slack

05/04/2023

Join the ångstromCTF slack!


widget

05/04/2023

I seem to have lost my gadgets.


Horsetrack

05/04/2023

I'm starting to write a game about horse racing, would you mind testing it out?


VNE

05/04/2023

We've got a binary that can list directories as root, try it out !!


babygame01

05/04/2023

Get the flag and reach the exit.


babygame02

05/04/2023

Break the game and get the flag.


hijacking

05/04/2023

privilege escalation


tic-tac

05/04/2023

TOCTOU


two-sum

05/04/2023

compilers are too smart


Bank

05/04/2023

I came up with this banking system that lets you deposit as much as you want. I'm not sure why, but my friend said it was a terrible idea...


Contrived Shellcode

05/04/2023

There's a 0% chance this has any real world application, but sometimes it's just fun to test your skills.


Encryptinator

05/04/2023

I have made this super secure encryption engine. I'll encrypt any message and no one will ever be able to read it. Not even me!


Inspector Gadget

05/04/2023

Inspector Gadget gave me this binary with one goal. pwn.


Pointers

05/04/2023

I've been messing with pointers lately which never goes wrong, right?


Pwnme

05/04/2023

pwn me. that's it.


Randomness

05/04/2023

I made this program to test how srand and rand work, but it keeps segfaulting. I don't read compiler warnings so I can't figure out why it's broken.


Sea Shells

05/04/2023

Sally sold some seashells by the seashore. Try to guess how many she sold, I bet you will never be able to!


Unlucky

05/04/2023

Luck won't save you here. Have fun trying to get the flag!


snap circuits

04/26/2023

SMPC


Button

07/24/2022

How do we deal with lots of html.


Sequel Sequel

07/24/2022

I must confess I have never connected to a sequel database in a gui before.


Flagbot

07/19/2022

Discord Bot exploitation is rare but it exists.


Ogre

07/19/2022

Portainer is a nice web ui for doing things with docker.


Score Hacker

07/10/2022

First CS "writeup" here!


Survey

07/10/2022

ez


vsCaptcha

07/10/2022

captcha looks solvable programatically. oh no deno


HSGTF

07/08/2022

tldr we should organize our past ctf conversations better.


Baby-RSA

06/10/2022

random useless information


Eunectes Murinus

06/10/2022

Oh look it's a python compiled file that guards a flag. Can we decompile?


Hacking Part 2

06/10/2022

Eljimike is back at it again with his weird hacking contests. Can you help him this time?


Hacking

06/10/2022

Help Eljmike organize his hacking contest!


Markdown++

06/10/2022

Parsers are fun especially when they're buggy (ahem ahem ahem DOMPurify).


OTP

06/10/2022

the one-time pad (OTP) is an encryption technique that cannot be cracked Wikipedia


Tunnels

06/10/2022

Catch b40m1k3


Parity

05/12/2022

Check your parity.


Dreams

05/11/2022

Sometimes I want to just stay in my dreams.


Bit Flipping Machine

05/08/2022

We just made a machine that can remotely flip bits to change the memory contents of enemy computers. You are tasked with demonstrating the power of this machine...


Internprise Encryption

05/08/2022

Our new intern Dave encrypted all of our important company files with his homemade "military grade encryption scheme" to try and improve company security...


Oil Spill

05/08/2022

Darn, these oil spills are going crazy nowadays. It looks like there's a little bit more than oil coming out of this program though...


Oracle

05/08/2022

An oracle is a black box in a Turing machine. You can run it but how do you inspect it?


Secure Horoscope

05/08/2022

Our horoscope developers have pivoted to a more security-focused approach to predicting the future. You won’t find breaking into this one quite so easy!


basic-mod1

03/29/2022

We found this weird message being passed around on the servers, we think we have a working decryption scheme.


basic-mod2

03/29/2022

A new modular challenge!


credstuff

03/29/2022

We found a leak of a blackmarket website's login credentials. Can you find the password of the user cultiris and successfully decrypt it?


morse-code

03/29/2022

Morse code is well known. Can you decrypt this?


Operation Orchid

03/27/2022

Sleuth kit on disk image


Wizardlike

03/16/2022

Do you seek your destiny in these deplorable dungeons? If so, you may want to look elsewhere. Many have gone before you and honestly, they've cleared out the place of all monsters...


GDB Test Drive

03/15/2022

Can you get the flag? Here's the test drive instructions:


Safe Opener

03/15/2022

Can you open this safe? I forgot the key to my safe but this program is supposed to help me with retrieving the lost key. Can you help me unlock my safe?


Bloat.py

03/15/2022

Can you get the flag? Run this Python program in the same directory as this encrypted flag.


file-run1

03/15/2022

A program has been provided to you, what happens if you try to run it on the command line?


file-run2

03/15/2022

Another program, but this time, it seems to want some input. What happens if you try to run it on the command line with input "Hello!"?


Patchme.py

03/15/2022

Can you get the flag? Run this Python program in the same directory as this encrypted flag.


Unpackme.py

03/15/2022

Can you get the flag? Reverse engineer this Python program.