The rundll32.exe process is responsible for running DLLs and placing its libraries in the memory. The rundll32.exe process is known as a command line utility program, and it performs its embedded functions along with the rundll.exe file. Rundll32.exe works by invoking a function that is exported from a specific 16-bit or 32-bit DLL module. However the only DLLs that you can call with the rundll.exe and rundll32.exe files are the ones that are only specified to be accessed by these processes.
The rundll32.exe file operates by parsing the command line. The specified DLL is then loaded through the function LoadLibrary(). Afterwards, from the function , it gets the addresses through GetProcAddress(). The command line tail is passed when the is called. Next, the DLL is unloaded upon the return of . Finally, the rundll32.exe file exits.