Too Many Colors Writeup
Challenge link => https://ez.ctf.cafe/
Before I go through the solving process, I’d liike to thank the organizers for making this fun event possible
CTF Cafe’s twitter
Alright so let’s get started by looking at this nonsensse of an image.
At first I went through a rabbit hole and tried getting each pixel’s hex value and converting it to ascii. SPOILER ALERT - It didn’t work.
I stumbled upon this article: https://omniglot.com/conscripts/hexahue.php, and tried decoding it by hand. Soon I noticed the original image was upside down, so I rotated it using gimp and saved it as a new image that looked somewhat like this
I also found this tool: https://github.com/kusuwada/hexahue, but couldn’t get it to work as the pixels in the image would be of a slightly different color, and python was freaking out.
After succesfully decoding the image to a string, we get “KC4LBT1TN14PU0YN4C7VB3RUS”. Looks like it’s inversed. Let’s fix that!
echo "KC4LBT1TN14PU0YN4C7VB3RUS" | rev
>> "SUR3BV7C4NY0UP41NT1TBL4CK"
Putting that into the required format, we get the flag: “EZ-CTF{SUR3_BV7_C4N_Y0U_P41NT_1T_BL4CK}”