Surfer

https://tryhackme.com/room/surfer

Nmap

sudo nmap 10.10.133.231 -p- -sS -sV

PORT   STATE SERVICE VERSION
22/tcp open  ssh     OpenSSH 8.2p1 Ubuntu 4ubuntu0.4 (Ubuntu Linux; protocol 2.0)
80/tcp open  http    Apache httpd 2.4.38 ((Debian))
Service Info: OS: Linux; CPE: cpe:/o:linux:linux_kernel

Web Server

The root page for the web server takes us to a login page.

Trying some standard credentials we are able to gain access with admin:admin. After login we are presented with the dashboard for 24X7 System+.

Inspecting the Admin's profile we take notice that the admin has mentioned a tool they have created that generates reports in pdf.

Going back to the dashboard we can see the button for exporting to pdf.

Testing the button we observe that by default this prints out the page located on http://127.0.0.1/server-info.php.

Using feroxbuster we enumerate for further files and discover the existence of /internal/admin.php.

 feroxbuster -u http://10.10.133.231/ -w /usr/share/seclists/Discovery/Web-Content/common.txt -s 200 

Running curl against the file we are given the message "This page can only be accessed locally."

curl http://10.10.133.231/internal/admin.php

Looking again at the tool for exporting2pdf we view the page source and can see where the tool takes the parameter "value=<url>".

Using the browser's inspector we change the value for value= to point to http://127.0.0.1/internal/admin.php. As this file can read locally we should, hopefully read the admin.php file.

After updating the value in the browser inspector and running the tool again we are now able to read the room flag in admin.php.