Cloud Service Users Exposed: Monster Cloud Free 5 Leak Hits 18,548 Records

In October 2023, analysts tracking Telegram-based threat actor activity discovered a stealer log file labeled Monster Cloud Free 5 that had been uploaded to a public channel by an anonymous user. The file contained 18,548 records pulled from infected endpoints, with data including email addresses, plaintext passwords, and API host URLs. The exposure of cloud-related credentials in this log makes it particularly risky for individuals who rely on cloud storage, SaaS platforms, or remote work tools in their daily routines.

Why This Is Dangerous

The combination of plaintext passwords and API host URLs in this log gives attackers direct access to both personal and cloud-hosted resources. Unlike hashed passwords that require cracking, plaintext credentials can be used immediatly. If the API endpoints belong to cloud services or workplace tools, attackers can access file storage, internal communications, or even billing accounts without any additional effort. This type of data is especially valuable for targeted attacks against businesses whose employees were among the 18,548 affected users.

What Was Exposed in the Monster Cloud Free 5 Leak

• Email addresses
• Plaintext passwords
• API host URLs and endpoint data

Why This Matters

Cloud credentials are among the most valuable assets a cybercriminal can obtain. When passwords for cloud services are leaked in plaintext, attackers can access file repositories, backups, and integrated applications with a single login. Credential stuffing tools allow criminals to test these combinations across dozens of platforms simultaneously, meaning one entry in this log could lead to account takeovers across multiple services. Identity theft, financial fraud, and corporate data theft are all realistic outcomes when cloud account credentials end up in a stealer log circulating on Telegram.

How Stealer Logs Work

Infostealer malware typically arrives through phishing emails, pirated software, or malicious browser extensions. Once running on a device, it scans for saved passwords in browsers, captures keystrokes, and copies session tokens from active logins. The harvested data is bundled into a log file and sent to the attacker's server. These logs are then organized by category, such as cloud services or banking sites, and sold or shared in underground markets and Telegram channels. The Monster Cloud Free 5 label suggests this particular log was sorted and packaged to highlight cloud-related credentials, making it a targeted resource for attackers focused on that vertical. Each record in the file represents a seperate infected machine.

Check If You Are Affected

Victims of stealer log breaches often don't recieve any notification because there is no single organization responsible for alerting them. HEROIC's free breach scanner searches across more than 400 billion exposed records, including stealer log data like the Monster Cloud Free 5 file. If your email address appears in this dataset or any other known breach, you'll find out in seconds. Enter your email address now and see if your credentials have been comprimised before an attacker uses them against you.