My guess, its a service contractor type situation, like getting a smart meter. You can opt out, you just wont have power.
They had a contract with a fridge company, and the service agreement required remote monitoring such that, the service company would be able to detect and troubleshoot remotely, and schedule calls.
The problem with situations like these is that your network security falls to the lowest common denominator, which in this case, is a group of HVAC technicians.
The conversation was something like this:
HVAC company: "Oh yeah, our software does this, and that, and we monitor everything, and thats why our contract is less, we dont waste time and we use sophisticated technology. And of course its 100% secure because expert boffins wrote it."
Grocer w/ 2% margins: "Sounds great."
To be clear, I'm not throwing shade on HVAC technicians. I'm only saying, they aren't network security specialists, thats all.
In the 2013 Target attack, the attackers used the HVAC contractors' credentials to gain access to Target's systems. The point of sale credit card terminals (what customers swiped cards and enter PINs) had no real security so the attackers were able to make those get "updates" from their own servers and download malware enabling them to get the magnetic stripe information as well as PIN (for debit cards). That year, I (like about 150,000,000 other people) got a brand new credit card with a new credit card number.
https://krebsonsecurity.com/2015/09/inside-target-corp-days-...
Newer PCI standards require much more secure customer-facing terminals and much more secure back-end systems so that much of this attack could not happen again.
https://en.wikipedia.org/wiki/Payment_Card_Industry_Data_Sec...
> Grocer w/ 2% margins
You have clearly never stepped foot inside an Albert Heijn store.
Somebody wrote the software that is the interface between the fridge and the internet. And while it would be nice if HVAC technicians would remember to only make this software accessible via VPN, it is in fact possible to write software that is reachable from the internet while still being secure
Given that we agree that HVAC technicians can't be relied on for network security, this is 100% on the fridge company for having insecure software. If it's a bad password or an unchanged default password that's still on the fridge company for not enforcing something better