LSASS is Local Security Authority Service. (Handles Windows security mechanisms. It is a system process.)
CSRSS is Client Server Runtime Server Subsystem. (Handles Windows and graphics functions for all subsystems. It is a system process.)
SMSS is Session Manager Subsystem. (Initializes system environment variables, MS DOS device names such as LPT1 and COM1, loads kernel for Win32 subsystem ans starts the Windows log on process. It is a system process.)
So you should not shut those down. They're fine
