While these tools were once highly effective, modern email security has largely neutralized basic SMTP cracking through:
Modern SMTP servers (like those from Google or Microsoft) quickly detect and block IP addresses that attempt multiple failed logins.
In the mid-2000s and early 2010s, tools like Sanmao SMTP Mail Cracker became popular in underground forums. They were designed with simple graphical interfaces, allowing users to load thousands of proxies and combolists to bypass security rate-limiting.
Today, "V2" or "2.0" iterations are often found on sites like GitHub or niche hacking communities. Modern variants, such as SMTP Heist or Aron-Tn's Cracker , are frequently written in Python and include features like real-time result tracking via Telegram.