The rainmail.biz Leak Exposed 674 Emails Just Weeks After It Happened

HEROIC Analysts Uncover the rainmail.biz Combolist

HEROIC's dark web monitoring team identified a combolist tied to rainmail.biz that was uploaded to a Telegram channel on June 10, 2026. The file contains 674 records pairing email addresses with plaintext passwords and the URLs those credentials unlock, and it surfaced publicly just weeks after it was first put together.

Why This Is Dangerous

The passwords in this dump are recorded in plaintext, so anyone who downloads the file can read them instantly and try them against the matching account. There's no cracking or guesswork involved, just a direct login attempt using the exact URL the credentials are tied to. Any of the 674 affected users who reused that password elsewhere are exposed on more than just their rainmail.biz-linked account.

What Was Exposed

• Email addresses
• Plaintext passwords
• URLs linking each credential pair to the account they unlock

Why This Matters

Combolists like this one are built for speed: attackers load the file into automated tools and run credential stuffing attacks against hundreds of other sites in minutes. A reused password can hand over access to email, banking, or social accounts, opening the door to account takeover, identity theft, and financial fraud well beyond the original 674 records.

How Combolists Work

A combolist packages email or username and password pairs into a single file, often assembled from smaller leaks or reused credential lists and labeled by the domain or service they target, in this case rainmail.biz. Telegram makes it easy for whoever built this file to share it widely within days of putting it together.

Check If You Are Affected

Don't leave it to chance. HEROIC's free breach scanner checks your email address against a database of more than 400 billion leaked records, including combolists like the rainmail.biz dump, so you can find out immediately whether your credentials are exposed and act before someone else does.