The web hosting includes the server that serving the websites , websites that are hosted on that server and other platforms like payment processing APIs , support portals , billing portals , chat portals etc... Many of the things of opensource where security should be configured. The server should be secured with soft and hard firewalls , modsecurity etc.. the websites that are hosted should be updated , the server must have anti virus installed , securing access control of billing and support portals. So webhosting security contains all these contents security.