how did I lose $5000?

بِسْمِ اللَّـهِ الرَّحْمَـٰنِ الرَّحِيمِ

السلام عليكم ورحمه الله وبركاته

Hello my friends, my name is Youssef (matrex007).

Welcome back!

today i will talk about :

the importance of letters

First, you need to know that every response is different and can contain sensitive information that may pose a risk to the site. So, I decided to try a certain idea.

During my attempt, I performed a brute force on the usernames on the site and identified a specific phrase in the response: [invalid username.]

Notice the presence of the period (.) at the end of the sentence. If it’s missing, it could indicate something else.

I focused on the content of the response and noticed the absence of the period.

Then, I tried putting the username in the request while performing a brute force on the password. As you might expect, I found that this username actually

exists as soon as the period was missing in the response. This meant I was about to overlook it, and if I hadn’t solved the lab, I would have lost the challenge.

Important Note: Pay attention to the response — missing letters and symbols can indicate something significant.

Thank you!

إن أحسنت فمن الله، وإن أسأت فمن نفسي والشيطان