Repo files are the configuration files for yum sources (software repositories) in Fedora. A repo file typically defines the details of one or more software repositories, such as where to download packages to install or upgrade. The settings in the repo file are read and applied by yum. Incorrect configuration can cause service unavailability.
If files have been added to /etc/yum-repos.d on the host, carefully check the host environment for signs of intrusion and change the host user password.