Musubi

18 July 2022

by yunaranyancat

This is a writeup regarding a CTF challenge for the Battle of 1337 CTF hosted by Tenang Komuniti Sdn. Bhd and Yayasan Digital Malaysia.

CTF1337

You can download the source code here.

First, you will be greeted by this locked page.

lockedpage

By inspecting the element, it shows a text and an ASCII art of the infamous Mr Trollface.

trollface

The password to unlock the page is obvious : DOWN HERE

When the page is unlocked, this page will be shown,

intro

Disable the jumpscare by unticking the events on the secret field so you will be able to submit the secret.

disablejumpscare

For those who are curious, this is the jumpscare;

jumpscare

By going to the debugger, there’s an interesting js file, filled with Mr Trollface ASCII art, again.

dbugger

On line 88, you will find a long string of obfuscated javascript code.

line88

Decode it using de4js with paramater set to eval. Here you will see that to unlock the page, you will need to concatenate all of the character taken from the string c.

de4jseval

I’ll let you sort it by yourself. ;)

free

And the end.

end

it’s not that troll-ish , isn’t it? (>‿◠)✌

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