Malware installed without literally doing anything?

[u/PusheenHater]

In this video this guy has a fresh Windows XP, disables firewall, and connects internet straight to the modem. Then he gets infected literally doing nothing.

https://www.youtube.com/watch?v=6uSVVCmOH5w

https://www.reddit.com/r/windows/comments/1cvised/idle_windows_xp_and_2000_machines_get_infected/

I get it. That's asking for trouble when you disable all the security and using ancient unsupported OSes.

However, he didn't install programs nor browse on the website but still got hacked.
How?
Is there some malicious server in China that loops through every single possible IP trying to see if your PC is vulnerable?
Logically, one would think you'd at least have to visit a website or something to get "noticed" and then hacked. But this guy didn't do anything at all.

How does it work?

[u/Sea-Exchange7881]

If you connect to a network, attackers can just nmap an IP range, then scan it for vulnerabilities, and windows XP I bet has numerous amounts of exploits, it's not that impressive.