./contents.sh

z0d1ak@ctf:~$ cat sections.md
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writeup.md - z0d1ak@ctf
Reverse Engineering
ACECTF
March 2, 2025
2 min read

ACECTF - Significance of Reversing

theg1239
z0d1ak@ctf:~$ ./author.sh

# Significance of Reversing

## Challenge Information

  • Category: Reverse Engineering
  • Points: 200
  • Solves: 187
  • Difficulty: Easy

## Description

Over the years, we hackers have been reversing stuff, thinking we understand how everything works and feel good about it. But, sometimes it feels like do we really understand what reversing means in mordern days? Anyways, here's a PNG, let's see if you can reverse your way out of this one.

## Files

Link to broken PNG file

## Approach

I downloaded the given file and ran the file command on it

file Reverseme.png
Reverseme.png: data

I thought of simply reversing the file based on opening the PNG file in a text editor

### Python Script

python
def reverse_png(input_file, output_file): with open(input_file, 'rb') as f: data = f.read() reversed_data = data[::-1] with open(output_file, 'wb') as f: f.write(reversed_data) reverse_png('Reverseme.png', 'original')

## Solution

Executing the Python script creates the original file that is reversed.

chmod +x original
./original

That gives us the flag.

## Flag

ACECTF{w3_74lk_4b0u7_r3v3r53}

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