Challenge

Information

Blame Game es un challenge de dificultad fácil dentro de la categoría General Skills de la plataforma picoCTF y fue creado por el usuario JEFFERY JOHN.

Description

Someone’s commits seems to be preventing the program from working. Who is it?

Hints

Hint 1

In collaborative projects, many users can make many changes. How can you see the changes within one file?

Hint 2

Read the chapter on Git from the picoPrimer here.

Hint 3

You can use python3 <file>.py to try running the code, though you won’t need to for this challenge.

Download

root@kali:~ ❯ wget -q --no-check-certificate "https://artifacts.picoctf.net/c_titan/73/challenge.zip"

Solution

File

Unzip (challenge.zip)

Descomprimo con unzip el archivo chalelnge.zip

root@kali:~ ❯ unzip -q challenge.zip
                                                                                                                                                                                         
root@kali:~ ❯ ls -l
.rw-r--r-- root root 287 KB Tue Mar 12 00:49:03 2024  challenge.zip
drwxr-xr-x root root 4.0 KB Sat Mar  9 22:09:11 2024  drop-in
Check (drop-in/)

Accedo al directorio drop-in/, y en él existen los siguientes archivos:

root@kali:~ ❯ cd drop-in 
                                                                                                                                                                                         
root@kali:~/drop-in ❯ ls -la
drwxr-xr-x root root 4.0 KB Sat Mar  9 22:09:11 2024  .
drwx------ root root 4.0 KB Sun Feb 22 11:06:22 2026  ..
drwxr-xr-x root root 4.0 KB Sat Mar  9 22:09:19 2024  .git
.rw-r--r-- root root  22 B  Sat Mar  9 22:09:11 2024  message.py
git
log (commits)

Con git reviso el historial de commits que afectan específicamente al archivo message.py.

root@kali:~/drop-in ❯ git log -- message.py 
commit fadeca9476b6713ec8cdda633aca9e9aebffc698
Author: picoCTF{@sk_th3_1nt3rn_XXXXXXXX} <ops@picoctf.com>
Date:   Sat Mar 9 21:09:11 2024 +0000

    optimize file size of prod code

commit 2dd46769e2d65656bb14aed0ff5d3237daaa7d9d
Author: picoCTF <ops@picoctf.com>
Date:   Sat Mar 9 21:09:11 2024 +0000

    create top secret project

Flag

Consigo leer la flag dentro del historial de commits.

root@kali:~/drop-in ❯ git log -- message.py | grep -oP 'picoCTF{.*?}'
picoCTF{@sk_th3_1nt3rn_XXXXXXXX}

Hasta aquí la resolución del challenge Blame Game de picoCTF.

Happy Hacking!