The Monster Cloud Free 2 Stealer Data Quietly Appeared on the Dark Web Last Week

Security researchers came across a stealer log file on Telegram in October 2023 going by the name Monster Cloud Free 2. The upload contained 21,990 records taken from infected computers, with each record including an email address, a plaintext password, and the URL of a site or service that password was used on. The file was shared publicly in a Telegram channel, meaning anyone who found it could download and use the credentials immediately. The people whose information was in that file had no warning it was happening.

Why This Is Dangerous

With 21,990 sets of working email and password combinations available in one file, attackers have a large collection of ready-to-use credentials. They can run those combinations through automated login tools against popular websites and services in a process known as credential stuffing. If even a fraction of those passwords are reused on other accounts, attackers can break into email inboxes, bank accounts, social media profiles, and more. The included URLs also tell attackers exactly which services each credential was already confirmed to work on, removing any guesswork.

What Was Exposed in the Monster Cloud Free 2 Stealer Log

• Email addresses
• Plaintext passwords (fully readable, no decryption needed)
• Website and service URLs associated with each credential pair
• Endpoint and device identifiers from infected machines

Why This Matters

A leak of this size with plaintext passwords is a direct launchpad for account takeovers. Criminals do not need any technical skills beyond running freely available software that tries each username and password combination across hundreds of sites automatically. Victims often do not find out their accounts have been accessed until money is missing, a recovery email has been changed, or their identity has been used to open new accounts. Credential stuffing attacks from leaks like this one contribute to millions of account takeovers every year.

How Stealer Logs Work

Infostealer malware is a program that hides on someones device after they click a bad link, download a fake program, or open a malicious file. Once installed, it silently reads through saved passwords in web browsers, captures login sessions, and collects any credentials stored on the machine. It then packages all of that into a log file and sends it back to whoever is running the malware. Those log files get uploaded to Telegram channels or sold on dark web forums. The original device owner often has no idea this occured, and the malware may continue running long after the log has already been shared.

Check If You Are Affected

HEROIC's free breach scanner checks your email and passwords against a database of more than 400 billion exposed records, including stealer logs like Monster Cloud Free 2. You can run a free check at HEROIC.com in seconds and see exactly which of your credentials are already circulating among criminals online.