Now that SSH is working on both hosts, we need to set up the reverse SSH tunnel. Taking a look at the following figure showing a simplified topology, there is a pretty big problem here that justifies why we need to set up a reverse SSH tunnel:
Do you see it? Well, in case you don't, the issue is that our internal Raspberry Pi server is not reachable externally, since the corporate firewall is blocking it. There are no inbound rules or NAT polices in place to handle this sort of connection. So I have no issues connecting to the C&C server; however I will need to have the C&C server connecting back to the Raspberry ...
