Unlike a targeted exploit that hacks into a specific server via software vulnerabilities, Hackus relies on the concept of credential reuse. It automates the process of testing thousands of previously leaked email/password combinations per minute across various mail services (Gmail, Yahoo, Outlook, Yandex, and private corporate domains).

Key functionalities often advertised by the creators of such tools include:

Since the software is typically sold or licensed by its developers, a thriving ecosystem of cracked versions has emerged. This elevates the risk of this tool from a specialized threat to a widespread one. The cracked version of Hackus Mail Checker 2.2.0 was leaked online by an individual known as "VortexVot," making it freely available to any aspiring cybercriminal. A repository named UniversDevs/HMC2.2.5 explicitly advertises "Hackus Mail Checker 2.2.5 Cracked". The availability of cracked versions dramatically lowers the barrier to entry for credential-stuffing attacks.