Eddy
2
rpcss.exe is an executable of Microsoft Windows Operating System. It is reponsible for Remote Procedure Call services on the local machine. These are public services available to the local network. This program is important for the stable and secure running of your computer and should not be terminated.
The RPC is vulnerable to attacks if your OS is not up-to-date.
Avast is not using port 135 to my knowledge.