Summary
Nagios-statd Daemon is running at this port.
Nagios-statd (nagios-statd Daemon) is the daemon program for nagios-stat. These programs together comprise a systems monitoring tool for various platforms. It is designed to be integrated with the Nagios monitoring tool, although this is not a requirement.
Nagios-statd is the daemon that listens for connections from clients. It forks off a new daemon for each incoming connection.
The forked daemon executes a series of typical UNIX commands and returns those commands standard output to the client.
Solution
Limit incoming traffic to this port.