How third parties generate valid pins for locked to the network devices

[m0nix]

I was wondering do they cooperate with operators worldwide, maybe they gave them access to the database if they pay fee?

But maybe those services use leaked software that calculates the pins by given imei.
I searched a lot for software that calculates unlock pins by given imei but all that i found was old software for old devices.

Can someone give me information on this topic?