The default username and password for SSH, (S)FTP and SMB in OSMC is:

username: osmc
password: osmc

Changing the default password

To change the default password for the osmc user, run the following command:

passwd

Enabling root access

By default, OSMC ships with the root user disabled, but allows privilege escalation with the sudo command. If you would like to enable the root username, run the following command:

sudo passwd root