对敏感文件类型统一拒绝：

The .shtml extension denotes a file that uses Server Side Includes (SSI) . Specifically, view.shtml is a common default filename used by various brands of network cameras (IP cameras) and digital video recorders (DVRs).

When a web server receives a request for a folder directory that does not contain a default homepage file (like index.html or index.php ), it can respond in two ways. It will either block access with an error code, or it will display a literal list of all files inside that directory. This automated list is typically titled at the top of the webpage. 2. "view.shtml"

The Security Risks of "index of view.shtml" and How to Protect Your Server