2 minutes
Art
Note to fellow-HTBers: Only write-ups of retired HTB machines or challenges are allowed.
Challenge info ¶
Art [by hexp]
Can you find the flag?
The challenge ¶
We start of by downloading the art.zip file and verifying it’s sha256sum with the hash displayed on the challenge page.
$ sha256sum art.zip
9ae27f1b71d22cb49f473630699d79d353db49e6b9e6d0a51cfcf268e753b48e art.zip
We then proceed to unzip this file using the password provided on the challenge page. This will give us a png image.
$ unzip art.zip
Archive: art.zip
[art.zip] art.png password:
inflating: art.png
Opening this image in the default image viewer returns a very colourful spiral.

Into the rabbit hole ¶
As most people, from what I could deduce from the forum, I immediately jumped to the conclusion that this is a steganography challenge.
So I loaded up some stego tools in an attempt to discover the hidden message. I used steghide, stegosuite, exiftool, zsteg and even briefly tried to find a logic in the colours.
People are weird ¶
However, some hints on the forum about programming languages and esoteric stuff made me google the correct keywords in order to find a Wikipedia page on Esoteric programming languages. It seems that people like to design the most mind-boggling programming languages for various sorts of reasons…
Eventually I discovered the image was probably an output of a program written in the Piet programming language. Luckily the Wikipedia page contained some images of programs written in Piet, making it easy to spot.
Getting the flag ¶
I had some issues in finding a working interpreter, but finally stumbled upon an online one, yay!
I uploaded the image and the following output returned:
HTB{p137_m0ndr14n}? ? $? ? 18? 32464? ? ? 8? ? ? ? [... a lot more ?s ...]
And there you have the flag: HTB{p137_m0ndr14n}
.
This challenge was weird, but I liked it :)
Thank you, Hexp!