ctf-writeup/Google CTF 2023/Papapapa

Papapapa

Is this image really just white?

About the Challenge

We have been given an image (Blank image), and we need to find the flag inside the image (You can download the file here)

How to Solve?

At first, I tried everything I knew to perform forensic analysis on a jpg file. I used various techniques such as employing steghide, altering the contrast, using binwalk, and more. However, I didn't find any significant results. During my search, I came across a blog titled "Hiding Information by Changing an Image's Height", which discusses a method of concealing information within an image by modifying its height and width.

First, im using CyberChef and then input the image there

Grab the hexadecimal, and then use it as an input. Find ff c0 00 11 08 ?? ?? ?? ?? value

The first 02 00 is the image height and 02 00 is the image width. Change the image width from 02 00 to 02 10 to read the flag

CTF{rearview-monorail-mullets-backroom-stopped}