Penetration through Wired NIC

I wonder if anyone has an answer or a thought to this. Wifi card has been removed from a laptop to preclude hacking in through neighboring wifi. Hackers continued to have access. Presume this is being accomplished somehow through the onboard NIC, which enables wired connection. They already had access, so likely embedded some kind of rootkit/backdoor (or some other mechanism the nature of which I am unaware). To the knowledge of the people on this forum, is there any way to hack into a device through neighboring wifi where the wifi card has been removed, but they had prior access? Also, is there any way, without having had prior access and the opportunity to install some type of rootkit or backdoor, to penetrate, say, a desktop without wifi capability, through neighboring wifi? What would have to be present in that laptop/desktop in order to penetrate it through neighboring wifi, where there is no wifi capability in that device? Any responses would be greatly appreciated.