InformationVerify that the '/etc/default/docker' file ownership and group-ownership is correctly set to 'root'.
'/etc/default/docker'file contains sensitive parameters that may alter the behavior of docker daemon. Hence, it should be owned and group-owned by 'root' to maintain the integrity of the file.
Solutionchown root:root /etc/default/docker
This would set the ownership and group-ownership for the file to 'root'.
This file may not be present on the system. In that case, this recommendation is not applicable.