Some modems come with remote administration access enabled, which can allow you to access your network settings while away from the home. However, if you have the ability to access your home WiFi network from anywhere in the world, this means a cybercriminal might be able to as well. One way to strengthen your home WiFi security is to disable remote access.
For most CenturyLink modems, you can find this setting, called "Remote GUI," in the Advanced Setup section of the user interface. See detailed instructions >