If the WiFi router is password protected the hacked refrigerator or other device cannot access it unless/until the homeowner brings it into his network via entering the password into the device’s interface. Until then the infected device is blind to the world.
So really it’s looking for unsecured access points. -Just like every other hacker out there.
But if you just spent a ton of money on your new WiFi enabled refrigerator, why wouldn't you give it your password so you can constantly monitor your produce drawer temperature.?
I'm sorry, Dave, but I've been talking to your scale this morning. You are only getting fresh vegetables and water until you've lost 20 pounds.
Surely none of those WiFi routers have an embedded chip or code that allows someone to hack in. ; )
...but configuring the fridge to talk on your WiFi network is one of the first things you’ll do when installed. This is “Trojan Horse” in a very real sense.