Researcher reports that stolen credentials are distributed for free on the dark web

If you're reading this article, it's time to change all your passwords.

This is because there is a good chance that your login information - or at least a previous version of it - is circulating on the secret networks (on the dark web) where hackers trade in stolen passwords.

These secret networks are constantly growing, according to Alex Heid, lead researcher and developer SecurityScorecard, a security company at cyberspace.

"In the underground hacking community, credentials are bought, sold and traded for free like Pokémon cards," Heid told Business Insider. "There are dozens of different hacking forums that contain terabytes of information at least 10 years back."

These forums work primarily on the dark web, a network of encrypted sites that do not appear on algorithms search. The login credentials and passwords that end up in these dark web forums usually come from huge breaches data, which often happened throughout the previous year.

Hackers are using increasingly sophisticated database software to compile "combinatorial lists" of millions of login credentials, according to Heid.

Even if hackers only have a set of credentials - for example, DoorDash users - they can easily access user accounts on other sites. Hackers use "checkers" or programs that can get one's email address user and quickly determine if it is used by others websites. From there, hackers usually try to link to these other sites using the same password, betting that objectives they use the same password on all platforms. In many cases, they are successful.

With the hacking to become ever more profitable and hacker software to become more sophisticated, there is no indication that this trend will slow down soon. In the meantime, Heid advises users to change their passwords and ensure that passwords are different on services that they use.