How the klaus_cloud_public Malware Led to 11,146 Stolen Logins

In October 2023, security analysts identified a stealer log file that had been uploaded to a public Telegram channel. The file was labeled klaus_cloud_public 522logs and contained 11,146 records pulled from infected computers. Every record included an email address, a plaintext password, and a URL pointing to the website or service where that login was active. The data did not come from a single company getting hacked. It came from malware silently running on individual people's computers, collecting every saved password it could find before sending the data to whoever was controlling it.

Why This Is Dangerous

Plaintext passwords paired with email addresses and website URLs give attackers a complete package. There is no cracking, no guessing, no extra steps. An attacker can take each record and log straight into the account it belongs to. From there they can take over email inboxes, raid online shopping accounts, access cloud storage, or pivot into workplace tools. The API host URLs included in this log suggest some of these credentials were used to access backend systems, which could mean business accounts and internal platforms are exposed too. Stolen credentials like these are often tested within hours of being posted.

What Was Exposed in the klaus_cloud_public Stealer Log

• Email addresses
• Plaintext passwords (unencrypted and ready to use immediately)
• Website and API host URLs associated with each login

Why This Matters

A stealer log posted to Telegram does not stay with one person. It gets downloaded and reshared across criminal networks almost instantly. Your email and password could be sitting in dozens of attacker databases right now. From there it feeds into credential stuffing campaigns, where automated tools try your login on hundres of different websites. Account takeover is the most immediate risk, but the damage often goes further into identety theft and finantial fraud. The longer compromised credentials stay active, the more damage they can cause.

How Stealer Logs Work

Stealer logs are produced by infostealer malware. This type of software gets onto a computer through everyday traps like a phishing email, a fake app download, or a malicious ad. Once installed, the malware runs quietly in the background and sweeps through the computer for saved passwords, active login sessions, and browser cookies. Everything it finds gets packaged into a log file and sent back to the attacker over the internet. The attacker can then search through hundreds or thousands of these logs, sorting them by website, country, or account type, before sharing them on Telegram or selling them on dark web markets.

Check If You Are Affected

HEROIC's free dark web scanner checks your email against over 400 billion leaked records, including stealer logs like the one from klaus_cloud_public. Find out in seconds whether your credentials have been exposed. Run your free check at HEROIC.com before your information gets used against you.