cd00r.c is a proof of concept code to test the idea of a completely invisible (read: not listening) backdoor server. Standard backdoors and remote access services have one major problem - the port's they are listening on are visible on the system console as well as from outside (by port scanning). To activate the remote access service, one has to send several packets (TCP SYN) to ports on the target system. Which ports in which order and how many of them can be defined in the source code.
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