Closing all external access to iMac

[Edhasbeenhacked]

Is there a way to close all external access to my brand new iMac? I’ve tried closing all the ports, modems, WiFi that I know of and still hackers are getting in. A back door perhaps? Any thoughts on locking them out? Or thoughts on how they are still getting in?
See low frequency post and
Super User post

 

[Cory Cooper]

Hello and welcome,

If you have no connection to the Internet by turning off Ethernet, Wi-Fi, etc., there isn't any way for hackers to get in. What have you noticed that makes you think your iMac has been hacked?

C