3.3 Ensure that docker.socket file ownership is set to root:root

Information

You should verify that the docker.socket file ownership and group ownership are correctly set to root.

Rationale:

The docker.socket file contains sensitive parameters that may alter the behavior of the Docker remote API. For this reason, it should be owned and group owned by root in order to ensure that it is not modified by less privileged users.

Impact:

None.

Solution

Step 1: Find out the file location:

systemctl show -p FragmentPath docker.socket

Step 2: If the file does not exist, this recommendation is not applicable. If the file exists, execute the command below, including the correct file path to set the ownership and group ownership for the file to root.
For example,

chown root:root /usr/lib/systemd/system/docker.socket

Default Value:

This file may not be present on the system. In that case, this recommendation is not applicable. By default, if the file is present, the ownership and group ownership for it should be set to root.

See Also

https://workbench.cisecurity.org/benchmarks/11818