The invention provides an application layer security method and system to secure trusted computer applications from executing out of their intended and authorized scope caused by illegal or harmful operation requests received from a distrusted environment. In an embodiment of the invention, a protective layer is implemented in between a trusted application and distrusted application operation requests. In operation, the protective layer identifies an application path of each operation request. Depending on the application path identified, one or more security pipes scrutinize the application contents of the operation request to determine if the operation request is illegal or harmful to the application or a surrounding environment.