1. A non-transitory computer readable medium storing instructions for replacement of at least one system function in an application with at least one customized function that causes the application to enforce at least one policy, the instructions, when executed by at least one processor, cause the at least one processor to: shift at least one existing load command in a file of the application away from a header of the file, the shift moving the at least one existing load command to a different location to accommodate at least one additional load command; add the at least one additional load command to the file, wherein the at least one additional load command identifies additional instructions that when executed cause the at least one processor to change at least one pointer of the application from a first value that points to the at least one system function to second value that points to the at least one customized function; and wherein the application is executed with the at least one customized function in an operating system to bypass at least one operating system restriction and enforce the at least one policy using the at least one customized function, and invocation of the at least one system function is preemptively redirected to the at least one customized function based at least in part on the at least one pointer that is changed.