1. A method for facilitating identifying a system call in an application and replacing the identified system call with a customized function call, comprising: upon a launch of the application, loading a hooking and injection manager into a process of the application prior to loading any modules in the application that make system calls; executing an executable file of the application, wherein the executable file has been modified to execute the hooking and injection manager at run time of the application, the hooking and injection manager including an interposition library configured to replace references to a system call with a respective reference to a customized function; and prior to the application making the system call: determining, from a symbol table, symbol table index values corresponding to one or more symbols associated with each system call in the application; determining, from an import table, an import table entry storing pointers to each respective system call based on corresponding symbol table index values; if the import table is a lazy symbol table, searching through a load command section of an application object file for at least one load command for a pointer holding an address of an indirect table and the lazy symbol table, wherein the address of the indirect table is stored in a _lazy_symbol section in the load command section and is associated with an S_RESERVED1 field in the _lazy_symbol_section in the load command section, and waiting until a respective system function call is called to change the pointers to each respective system call in the lazy symbol table so that the pointers to each respective system call are updated to indicate an address of the respective customized function call; and if the import table is a non-lazy symbol table, searching through the load command section of the application object file for at least one load command for a pointer holding an address of the indirect table and the non-lazy symbol table, wherein the address of the indirect table is stored in a _non_lazy_symbol section in the load command section and is associated with an S_RESERVED1 field in the _non_lazy_symbol_section in the load command section, and changing, prior to the application making the respective system call, the respective pointer to the respective system call in the non-lazy symbol table so that the respective pointer to the respective system call is updated to indicate the address of the respective customized function call.