1.2.3 Ensure gpgcheck is globally activated - CA that is recognized and approved by the organization.
The gpgcheck option, found in the main section of the /etc/yum.conf and individual /etc/yum/repos.d/*.repo files determines if an RPM package's signature is checked prior to its installation. Rationale: It is important to ensure that an RPM's package signature is always checked prior to installation to ensure that the software is obtained from a trusted source.
Edit /etc/yum.conf and set 'gpgcheck=1' in the [main] section. Edit any failing files in /etc/yum.repos.d/*.repo and set all instances of gpgcheck to 1.