About the rundll.exe or rundll32.exe files

Located in the folder C:\Windows\System32 the ‘rundll’ file makes possible to run a DLL file as an application placing its libraries in the memory for better performance.

A few examples the rundll32.exe file can do to execute some commands in command prompt:

- creating shortcut
– locking Windows workstation
– log off, restart or/and shutdown the computer
– start screensaver
– run copy disk

The rundll32.exe file can also be found in the Task Manager in the Processes list or sometimes appears as an error message when shutting down the PC.

Here is the sample of the syntax for the rundll32.exe file:
rundll32.exe <dllname>,<entrypoint> <optional arguments>

To understand better, here is an example how to open the Control Panel:
rundll32.exe SHELL32.DLL,Control_RunDLL desk.cpl,,0