I am building a server application that will maintain connections to other applications by initiating TCP connections out through a firewall that is only open for outbound traffic to the relevant IP's ports that the application will connect to.
What is the risk of someone having taken over the machine(s) we connect to being able to exploit our application backwards through the outbound connection that we have established.
The protocol used on the connection is not difficult to figure out but it's based on a periodic heartbeat (interval 30 seconds). If two successive heartbeats are missed, the initiater (us) will terminate the connection an reconnect.
The sourcecode or binaries for our application will not be available to the orginasation we connect to.