User: think outside of the box, dirb and gobuster can help you to find the URL, but actually you don’t need neither of them, the link is exactly in front of your eyes, just enumerate the page you see.
After finding the login page, find out what kind of database mango is using. search for privilege escalation for that service on google.
Root:
Not a big deal, GTFobins is your friend.
Great box, Thank You @MrR3boot