Background: 15 years of experience in software and apparently spoiled because it was already set up correctly.
Been practicing doing my own servers, published a test site and 24 hours later, root was compromised.
Rolled back to the backup before I made it public and now I have a security checklist.
Although disabling the root user is a good part of security, leaving it enabled should not alone cause you to get compromised. If it did, you were either running a very old version of OpenSSH with a known flaw, or, your chosen root password was very simple.
The latter. It was autogenerated by the VPS hosting service and I didn’t think about it.
It should be a serious red flag that your VPS host is generating root passwords simple enough to get quickly hacked.
I’m pretty sure they assumed if you bought their service, you have the competency to properly set it up.
And I proved them wrong.