WinRM is Microsoft's implementation of the WS-Management Protocol. This protocol is SOAP based, allows systems to access and exchange management information across an IT-infrastructure and handles authentication.
WinRM has superseded DCOM as recommended remote WMI protocol.
By default, WinRM uses Kerberos for authentication. So, Windows does not send the password to the system that requests a validation.
The WinRM service listens on TCP/IP port 5985 (by default).