I was listening to a Bazzell podcast where he mentions his company self hosting and maintaining a database of personal data and credentials for use in OSINT investigations. Some acquired through public sources but others acquired through leaks. Then of course there are data aggregate companies that do the same but are going on to sell this data for a profit.

What is the legality of this? Obviously acquiring publicly available data is legal, but how are these companies able to hold on to leaked usernames, passwords, and other confidential personal information. Especially those that were initially acquired through illegal means?