In Sweden, to avoid this kind of malicious leaks, we leak the residents' data officially. https://hitta.se lets you look up personal numbers, names, addresses, birthdays and sometimes phone numbers of any resident. The residents are not asked for consent, the data goes there automatically (some of my friends had success with having it removed from hitta, but it comes back once you change residence address).
It's quite convenient, when you meet a new friend, to go and check what neighbourhood they're from, who do they live with and where they lived before.
What's the big deal, Danes? What do you have to hide?
(The provocative tone is intentional as a joke, I'm not even a Swede, I just find the brotherly rivalry between Scandinavians amusing.)
I have been advocating for Denmark to do the same for 15+ years. The fact that your social security number can be used for anything on it's own is a disaster. Mostly it can't anymore, because you have to do electronic signing with MitID, but it's still considered secret. If you own a home in Denmark, address information is already public, but a little hard to lookup.
The problem with this leak mostly going to be those with hidden addresses or secret phone numbers. Last time something similar happened was when it was shown that you could pretty much just guess a persons social CPR number if you had their birthday. Normally you could narrow it down to 6 or 8 possible numbers then use the phone companies websites, pretend to create a new account, enter the CPR number and check if you guessed correctly. Because the demo was done with politicians, then phone companies no longer ask for CPR upfront.
I was actually surprised when I heard about this for the first time. Also I've heard that even the salaries of people are publically available. That's really cool.
Are there no murderers, crazy ex-boy/girlfriends, targeted harrassment and spam calls in Sweden?
Not that any other country does much better in this regard. Still it sounds a little wild to me that you can get this information without even needing to hit a shady forum and download some csv. Maybe lowers the bar too much.