Nice privesc! 
Thought it would be simple but it turned out trickier than I thought, which is a welcome surprise!
Not a fan of the phase from initial foothold to user though…
Some tips: (again if mods feel this is too spoilery please feel free to edit)
Initial foothold: If I gave you a CTF web problem that asks you to search something, what’s the first thing you should try?
User: Google around for some bypasses
Root: Just blindly following a certain well known website won’t give you everything, there’s more to it than what’s given.
As always, DM me for more tips!