writeups

itachi.md

Cyberlympics CTF

Steganography

Itachi

On 29th October 2023, my team participated in the Cyberlympics CTF final where I managed to solve some challenges. Lets start with the steganography challenge itachi. We are given a png image itachi.png with a description You have to use your inner sharingan to unlock the secret.

Solution

First download the image from the above link. You can use the command file to check what kind of file it is; | since it's a PNG file, we can now use our inner sharingan to unlock the secret that is hidden, from the decription we were given.But first let's view the image using eog(eye of gnome) eog Itachi.png

If you've worked on steganography before and especially using the PNG files, there is a tool you can use to unravel any data that is hidden: zsteg It's a great tool, that is what I used, also if you want to give more options you can use --help

Use the command zsteg -a Itachi.png

Scrolling down we can find something quite interesting;

We can take the string, and seeing it's reversed we can just run a small python script to reverse the strings;

And that's it, that's is our flag.

Toka

The challenge description was Can you find the hidden flag

Solution

First thing first is to run the file command on the file to check what type of file it's.

We can see it's a PNG file interesting We can decide to change the file extension to PNG or just run zsteg direct since it will still accept it. Using the command zsteg we get;

We get the flag.