I had a friend who was in the printing business and used these huge Xerox copiers. Xerox did the same thing that Deere was doing. They had a secret code to login to the copiers to “fix” it. Usually at a minimum of $250.00 a whack.
He got smart and installed a camera pointed at one of the machines he was getting ready to have maintenance done on and got the code.
No more Xerox calls.
Very smart. Many companies still don't understand how dangerous those copiers can be. They have hard drives in them that store just about everything you copy. Most also have servers built in as well. I'd definitely run portscans against any copier to see if there are any listeners, and would block any attempt to go to anything but a RFC-1918 address.