I encountered the following message when attempting to execute a sudo command on a freshly installed system:

[webdevelop@arkos01 ~]$ sudo su -
sudo: /usr/bin/sudo must be owned by uid 0 and have the setuid bit set

To fix this, I had to login as root via SSH (by setting the sshd config value PermitRootLogin to yes) and execute the following command:

chmod u+s /usr/bin/sudo