The CLOUDCOSMIC Stealer Log Data Quietly Appeared on Telegram in May 2023

HEROIC analysts confirmed a stealer log dataset known as 528 PCS - 27.05.2023 CLOUDCOSMIC uploaded by a Telegram User was circulating on Telegram as of May 2023. The file contained 7,644 records harvested from infected devices, including email addresses, plaintext passwords, and the URLs of websites where those credentials were used. The data was not obtained from a single company breach. It was assembled from dozens of compromised endpoints by malware designed specifically to extract login information.

Why Plaintext Passwords From This File Are a Serious Problem

Passwords stored or transmitted in plaintext have no protection at all. There is no hashing, no encryption, nothing standing between the credential and an attacker who downloads the file. Anyone who obtains the CLOUDCOSMIC stealer log can immediately attempt to use every password in it across popular online services.

The inclusion of URLs alongside each credential makes this dataset particularly useful to criminals. Rather than guessing where a stolen password might work, the attacker already knows exactly which website to target. This combination of email, password, and target URL is what security researchers call a "combo list," and it is among the most sought-after data on underground markets.

What Was Exposed in the CLOUDCOSMIC Breach

• Email Addresses: Primary identifiers used to access accounts across thousands of platforms
• Plaintext Passwords: Unencrypted, ready-to-use credentials with no decryption required
• URLs: Precise website targets telling attackers exactly where each password was used

Why This Matters: The Path From Stolen Credential to Account Takeover

When 7,644 sets of working credentials are freely available on Telegram, the risk is not theoretical. Credential stuffing attacks use automated tools to try these logins against banking portals, email providers, and e-commerce platforms at scale. A single successful login can allow an attacker to drain a bank account, lock the legitimate owner out, or sell access to other criminals.

Phishing is another common next step. Once an attacker has your email address, they can craft convincing messages impersonating your bank or employer. Combined with knowledge of which sites you have accounts on, those messages become definately more convincing and harder to spot. Identity theft and financial fraud often follow within days of a credential appearing in a leaked file like this one.

How Stealer Logs Are Created and Distributed

Information stealer malware is installed on a victim's device through methods like infected downloads, cracked software, or phishing attachments. Once active, the malware silently collects browser-saved passwords, cookies, autofill entries, and active session data. It packages everything into a structured log file and transmits it to the attacker's server.

The name "528 PCS" in this dataset likely refers to the number of infected machines, or "pieces," that contributed records to the final file. CLOUDCOSMIC appears to be the distribution channel or operator name. These logs are then uploaded to Telegram channels where subscribers can download them freely or at low cost. The person who uploaded this particular file did so on May 27, 2023, but the data may have been collected over a period of weeks or months before that date.

Victims have no way of knowing their information was captured untill they check a breach database or recieve an alert from a monitoring service.

Check If You Were Part of the CLOUDCOSMIC Stealer Log

HEROIC maintains a breach scanner backed by more than 400 billion compromised records, including stealer log files distributed through Telegram channels like the one that shared the CLOUDCOSMIC dataset. Searching your email address takes seconds and is completely free.

If your credentials appear in this file or any other known breach, HEROIC will show you exactly what was exposed and what you should do about it. Do not wait for an attacker to use your password before you find out it was stolen.