Question

Root Access With SSH - PermitRootLogin or PasswordAuthentication

Posted on January 20, 2017
Security
Asked by psmod2

Hi,

I just did a one click install of MongoDB. I’m SSH into the machine and its all ok.

Now, I want to disable password to the machine to prevent brute force, however two different articles are stating two different things to achieve this:

Is it:

PasswordAuthentication no

PermitRootLogin without-password

The later, I can’t actually see this in my /etc/ssh/sshd_config file.

Also by doing this I presume if I access the console via the Digital Ocean page, I can still use the password to login?

If not, then what would happen the certs on my machine went missing?

Thanks.

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Jonathan Tittle • January 21, 2017

Accepted Answer

@Woet

From a security standpoint, disabling root login and creating a sudo user is recommended – it’s what many would refer to as a best practice. Please don’t say it’s not important as that’s a misconception. When a sudo user is perfectly capable of handling root level commands and, unlike root, is not a well known and highly targeted user, there’s no excuse to allow root logins.

@psmod2

When it comes to security and preventing potential attacks, it’s best to simply create a sudo user and disable root login. The root user is well-known and will be the first one targeted by an attacker. When it comes to automated attacks, when root login is disabled, the login attempts will simply fail.

If you want to take things one step further, I would recommend that your sudo user not be a common user that is given ownership over any specific directories or files. When it comes to ownership of web-facing files and directories, you should create a user that has standard limited permissions.

Jonathan Tittle • January 20, 2017

@psmod2

Setting PasswordAuthentication to no enforces the use of SSH Keys for user accounts instead of plain-text passwords.

Disabling password authentication is far more secure and a much better option, though it does mean that you will have to keep up with your SSH Keys locally, otherwise you won’t be able to log in.

Woet • January 20, 2017

https://www.freebsd.org/cgi/man.cgi?sshd_config(5)

Console in DigitalOcean is unaffected since it doesn’t use SSH.