Linux

One always minimises attack surfaces and the possibility of fat fingered mistakes. The lower privileges that you grant yourself the better.

You'd think that Dave Cutler who, I believe, designed Windows NT coming from a Unix style background would have followed these principles but no. I discovered *nix late sadly.

The multi-tennant approach to the linux operating system isn't just for security. It's the way the OS was designed to operate. You're not meant to use root as an ordinary user.

Disabling root removes the safety net, but it also plugs the security hole that leaving root enabled leaves.

You can disasble passwords so ONLY keys work, and you can firewall ssh to ONLY IPs you originate from.

Its a concept called defense in depth. Without root login now you require the key AND sudo password.

Also, outside of self hosted you will have multiple people logging in. You want them to log in with their own users for logging and permission management.

Audit trails

1. Swiss cheese slices: make them holes too tight.
2. When you run everything as root, if you fuck your shit, your shit's fucked.

"Best practices" tend to come from other people's whoopsies. But it's always good to question things, too.

If ssh has a security issue and you permit root logins then hostiles likely have an easier time getting access to root on the machine than if they only get access to your user account—then they need multiple exploits.

Generally you also want to be root as little as possible. Hence sudo, run0, etc.

It's another slice of Swiss cheese. If the user has a strong enough password or other authentication method through PAM, it might stop or hinder an attacker who might only have a compromised private key, for example. If multiple users have access to the same server and one of them is compromised, the account can be disabled without completely crippling the system.

Using sudo can also help you avoid mistakes (like accidentally rebooting a production server) by restricting which commands are available to the user.

I never login with the root account. Not even on the console. You don't want everything you do running as root unless it is required. Otherwise it is much easier for a little mistake to become a big mess.

Yes it's always better to login with a user and sudo so your commands are logged also having disable passwords for ssh but still using passwords for sudo gives you the best protection