HNF 2025 - Git Commitment Issues

Challenge Description

Description

git commit -m ‘feat: IDK what I did, help ples’

• Author: Jun Wei
• Category: misc
• Difficulty: easy

Files

• calc.zip

Git Commitment Issues - Solution

As the challenge name suggests, this challenges revolves around the usage of Git.

1. For this challenge, we are provided with a zip file called calc.zip. The first step is to unzip this file, which should show many git-related files being extracted.

2. We can navigate into the extracted directory. There should be one file called calc.py, and it contains a Python script for a simple calculator app.

3. Since there are no other files (or branches actually), we probably need to look at the git commit history. We can do this using the command git log --all --oneline.

┌──(nepz㉿nepz)-[~/safe-calculator]
└─$ git log --all --oneline
14bafe0 (HEAD -> main, origin/main, origin/HEAD) add help command
784a872 add command menu (with clear command)
96102cf add square root
37654b2 add quit command for graceful exit
b678c57 add robust input validation
8ed3fc5 HNF25{g1t_15_4w3s0m3}
1dd3071 refactor operations handling with the use of dictionary
eabfe27 add modulo (remainder)
a7f664d add exponentiation (power)
d5692d1 implement main function
e8a1cbf allow user input
fce462a add basic calc

One commit message (HNF25{g1t_15_4w3s0m3}) closely resembles a flag. However, this is a decoy flag, not the real flag.

4. The next step is to list out which files were changed in each commit so that we can proceed further into the investigation.

git log --all --oneline --name-only

We can see that a file called flag.txt was included in 2 commits, namely 8ed3fc5 - HNF25{g1t_15_4w3s0m3} and b678c57 - add robust input validation.

5. We can check the status of this file to see what was happening in these 2 commits.

git log --all --oneline --name-status

We see that in the commit 8ed3fc5 - HNF25{g1t_15_4w3s0m3}, the flag.txt file was added. This file was deleted in the next commit (b678c57 - add robust input validation).

So, we can simply use a git show command to display the contents of the flag.txt file when it was added in the commit with the commit hash of 8ed3fc5.

┌──(nepz㉿nepz)-[~/safe-calculator]
└─$ git show 8ed3fc5:flag.txt
HNF25{v3rs10n_c0ntr01_w1th_g1t_c4n_b3_m3s5y}

Flag: HNF25{v3rs10n_c0ntr01_w1th_g1t_c4n_b3_m3s5y}