picoCTF HideToSee Writeup

In this challenge we are given a JPG file named “atbash.jpg”.

I used the pico webshell to complete this challenge.

First I downloaded the file onto the webshell via wget tool.

After that I looked around for some information using the file, binwalk, and strings command but I got nothing useful.

After that I used the steghide tool and found that it contained an encrypted.txt file.

steghide info atbash.jpg

Press enter when it asks for passphrase, and y to get information about embedded data.

After that, I use the following command to extract the file:

steghide extract -sf atbash.jpg

Now we have the encrypted text.

I headed over to the Atbash Cipher cracker.

… and there’s the flag!