The CLOUDCOSMIC Stealer Log Gave Hackers Everything They Need to Take Over Your Accounts

In June 2023, a Telegram user uploaded a stealer log file labeled CLOUDCOSMIC, exposing 6,373 records containing email addresses, plaintext passwords, and URLs. Unlike most data breaches where attackers still have to crack encrypted hashes, this dataset handed cybercriminals something far more dangerous: credentials that work immediatly, no decryption required. For every person in that dataset who has not changed their passwords, the window for account takeover remains wide open.

Why This Is Dangerous

Stealer logs capture credentials at the moment of infection, pulling them directly from browsers, saved sessions, and password managers on the victim's device. The CLOUDCOSMIC log is especially concerning because it includes plaintext passwords -- meaning attackers do not need to invest any time in cracking. They can immediately attempt to log in to email accounts, online banking portals, shopping sites, and corporate systems. With URLs also included, attackers know exactly which services each victim was using, making targeted attacks far more effecient.

What Was Exposed

• Email Addresses
• Plaintext Passwords
• URLs (revealing active accounts and services)

Why This Matters

When attackers gain access to a victim's email account, the damage cascades. Email is the master key: it controls password resets for banking, social media, cloud storage, and workplace tools. The 6,373 records in the CLOUDCOSMIC log represent 6,373 potential starting points for full account takeovers. Because the data includes URLs, attackers already know which services to target first. Three years after this log first circulated on Telegram, the credentials still work wherever victims have not updated their passwords.

How Stealer Logs Work

A stealer log originates from malware installed on a victim's computer, typically through a phishing email, a trojanized software download, or a drive-by browser exploit. Once running, the malware harvests every credential it can find -- saved browser logins, autofill entries, session tokens -- and transmits them to a remote server controlled by the attacker. The data is then packaged into log files and sold or freely shared in dark web marketplaces and Telegram channels. The CLOUDCOSMIC log followed this exact pattern, appearing in a Telegram upload in June 2023 and exposing records from hundreds of infected endpoints.

Check If You Are Affected

HEROIC's free breach scanner searches more than 400 billion exposed records to check whether your email address or passwords appear in datasets like CLOUDCOSMIC. If your credentials are found, change those passwords right away and activate two-factor authentication on every account that supports it. The sooner you act, the smaller the window attackers have to exploit your data.