Search Your Email: The 309logs Dump Exposed 5,987 Accounts

In November 2023, HEROIC's threat intelligence team discovered a stealer log file uploaded to a public Telegram channel by a user identified as "309logs." The file, linked to the klaus_cloud_public data set, contained 5,987 records harvested from compromised user devices. The data was exfiltrated using infostealer malware, which silently collects credentials stored in web browsers and applications before sending them to an attacker-controlled server. This type of breach does not require the targeted website to be hacked -- instead, it targets the person's own device.

Why This Is Dangerous

Stealer logs are particularly harmful because the passwords are captured in plaintext directly from the victim's device. This means attackers don't need to crack anything -- they recieve the credentials ready to use. Once a set of working credentials is in a stealer log, it can be sold, traded, or used for account takeover attacks within hours. Because most people reuse passwords across multiple services, a single stolen login can open doors to email accounts, banking apps, social media profiles, and more.

What Was Exposed

The following data types were found in the 309logs Telegram upload:

• Email Addresses
• Plaintext Passwords
• URLs (sites and services the victim was logged into)

Why This Matters

This breach is a clear example of how endpoint-level infections lead to credential theft at scale. The URLs included in the log reveal which services each victim was accessing, giving attackers a precise roadmap for where to use the stolen passwords. With 5,987 records exposed and distributed on a public Telegram channel, these credentials are easilly accessible to anyone looking to commit fraud or take over accounts. The seperate pieces of data -- email, password, and URL -- combine into a complete attack package.

How Stealer Log Breaches Work

Stealer malware typically arrives through phishing emails, fake software downloads, or malicious advertisements. Once installed on a device, it runs silently in the background, scanning browsers and apps for saved credentials. It also captures session cookies and autofill data. The collected information is then packaged into a log file and uploaded to a private server or, as in this case, a Telegram channel where other criminals can download it. The entire process can occured in minutes after the initial infection, long before any antivirus detects the threat.

Check If You Are Affected

HEROIC offers a free personal data scanner that checks your email address against more than 400 billion exposed records, including stealer logs like this one. If your credentials appeared in the 309logs dump or any other known breach, you will be notified immediately so you can take action before attackers do. Run a free scan now at heroic.com and find out if your data has been exposed.