If you ask: Where do cyber criminals get all their information?
I can answer you that...
For a cyber criminal it is important to know, how much money (at least the order of magnitude) a potential victim has.
It would look bad if they try to cheat a poor bloke for some millions.
For that reason it is extremely nice (sarcasm) that a Colombian bank puts millions of documents about their customers (credit authorizations, creditworthiness reports, etc.) online WITHOUT any authentication or authorization required.
In order to fulfill their duty to the criminals of the world, they also put scans of the officials ID cards of those citizens online too (of course both sides).
On some days I cannot eat as much as I want to throw up.
Such is life in #infosec
Currently I am busy with my contacts in Colombia to find someone to take care of that. It would be much easier if said bank would follow RFC 9116. But alas, no such luck.
I will name the bank once the leak is closed.