: These files are the fuel for credential stuffing attacks . Since many users reuse passwords across different platforms, attackers use automated tools to "stuff" these lists into various websites to see which accounts they can gain access to.

: Contains real, stolen credentials often tied to legitimate identities.

The "Mixed" designation in such a file indicates that the credentials have been aggregated from , such as different corporate data breaches, phishing campaigns, and malware logs (infostealer logs), rather than being a single dump from a single service. Key Characteristics of a Combolist

: They are frequently traded, sold, or shared for free on dark web forums, Telegram channels, and other underground marketplaces. Why "Mixed" Lists Are Dangerous

: Usually structured as username:password or email:password for easy ingestion by automated software.