When studying the behavior of trojans and (RAT) Remote Access Trojans this question came up.
Can an attacker create a trojan that could trick the OS or the NIC into hiding a remote connection to a computer so tools like Wireshark or Process hacker that can look at things such as active, listening, established connection wouldn't be able to see a remote connection to it so the attacker could make something like an invisible backdoor?
I know one way of accomplishing "invisibility" would be to encrypt a connection with IPsec so the whole packet payload+header would "hide" its identity even though a router would still know where it came from, I would like to know if is it possible to make a established connection "invisible" to Wireshark analysis.