Our Analysts Found the FASTCLOUDD Leak With 5,118 Stolen Logins

HEROIC analysts identified a stealer log file, labeled "FASTCLOUDD," uploaded to a public Telegram channel on December 22, 2022. The file contains 5,118 records made up of email addresses, plaintext passwords, and the URLs of the API hosts those credentials belong to. This data was not taken from one company's database. It was harvested directly from infected computers by credential-stealing malware.

Why This Is Dangerous

Because the passwords in this file are stored in plaintext, they can be used immediately, with no cracking required. Each record also lists the specific API host URL the credentials belong to, so whoever has the file knows exactly which service each login unlocks. That combination gives an attacker a ready-made list of accounts to target with working logins.

What Was Exposed

• Email addresses
• Plaintext passwords
• Associated API host URLs

Why This Matters

Because so many people reuse the same password across multiple accounts, a leak of this size fuels credential stuffing attacks, where criminals feed stolen logins into automated tools that test them against banking, email, and shopping sites. A single match can lead to account takeover, identity theft, and direct financial fraud.

How Stealer Logs Work

A stealer log is produced by malware that infects a device, quietly collects saved usernames and passwords from browsers and applications, and packages them into a file. These files are then shared or sold on Telegram channels and dark web forums, exactly as happened with FASTCLOUDD. Because the malware captures everything saved on the infected machine, a single compromised device can expose credentials for many unrelated accounts at once.

Check If You Are Affected

If you want to know whether your email address appears in this leak or another one, HEROIC's free breach scanner checks your information against a database of more than 400 billion leaked records. A quick scan shows whether your credentials have surfaced and what to do next.