Write-up on CTFlearn’s challenge 104 - Git Is Good! The flag is redacted… or is it? Challenge author: intelagent.


Forensics, 50 points

The flag used to be there. But then I redacted it. Good Luck. https://mega.nz/#!3CwDFZpJ!Jjr55hfJQJ5-jspnyrnVtqBkMHGJrd6Nn_QqM7iXEuc


As the title says, this challenge is about Git. If you don’t know Git yet, you should really learn more about it (resource here), since it is a primordial thing to know in programming these days.

Let’s download and extract the zip file from the Mega link and see what this is about. As you can see, we are given a Git repository containing only one file, flag.txt. The problem is that the flag has been redacted.

ZIP Content

Let’s take a deeper look at this repository using Git. I personally use GitKraken Git GUI as my Git client, but you can use any similar tool or even plain command-line Git. Commits

By moving through the commits, we can actually find a version in which the real flag was in the flag.txt file. Solution

That’s all we got to do to solve this challenge. If you have any questions, feel free to contact me via Twitter or using any of the methods listed here.