⛳️ picoCTF2022: Roboto Sans

Roboto Sans

AUTHOR: MUBARAK MIKAIL

Description

The flag is somewhere on this web application not necessarily on the website. Find it.

Check this out.

This challenge got me a while to dig in and find where the flag is. I might be overthinking at time but turned out it’s a classic one. Let’s dive in.

When going to the website, it looks like an under-development website. Looking all source files, not yet found anything. The clue said,

“on this web application, not necessarily on the website”

Alright, it has to be something behind the scene but part of it. Well, it could be XSS and get something but if looking carefully into .js file, the form on the website does basically nothing. Not even sending the form; thus, it’s not connected with the backend at all.

Alright, next could be some hidden paths and files. How to find it? One potential place to look for that is /robots.txt. Shall we go check it out?

Hah! got you!

Wait, really? NO, NOT YET. What are those alien languages 🤔

My first thought was encoding-decoding is everywhere. With my noob brain, I saw == at the end of the second line, which telling me it’s potentially encoded by base64. Let’s decode it. Heading to https://www.base64decode.org/ and paste those text.

The decoded message is

flag1.txtjs/myfijs/myfile.txt,z谖/u%z8

Potentially separated by ; and new line; thus I broke to new line and decode each line separately, and see what it got.

flag1.txt
js/myfi
js/myfile.txt
,z
(hnj^

Okay, now we have a lot more and greater idea where the flag can be stored at. Let’s go to each file and see. You shall see where the flag is 😉

And…you shall get 200 points to your scoreboard 🎖️