Some time ago I heard of HackTheBox and that looked very interesting, so I decided it was time to try it.
You can subscribe to it for a free account: you're given a openvpn config that make you access to some (~20 ) virtual machines.
With a small monthly fee you can also have access to other machines (~100) that have benn retired and you also have access to walkthroughs of these retired machines.
(the concept behind is that every week a public machines gets replaced by a new one while the replaced VM becomes retired)
The goal is to find a way into the machine and caputre a user and root flags.
Every flag give you points that are used to calculated your total score and ranking.
There are also side challenges similar to other CTF (like reversing files...)
So far I focused on easy/medium machines to solve and got root/admin on the following:
I wrote walkthrough for these machines, but I can't publish them, as they are still active and publicly available machines.
Once they get retired, I'll publish them.
So now the badge is: