One Telegram Upload. One Bonus File. StealC572 Had 9,458 Records.

In June 2023, a file named 20230527_stealc572_bonus surfaced on Telegram, uploaded by an anonymous user and containing 9,458 records harvested by StealC malware. The label "bonus" in the filename is a common signal used in stealer log marketplaces to denote a supplemental or high-value batch of stolen credentails. The records included email addresses, plaintext passwords, and the specific URLs the victims had been authenticated to when their devices were compromised.

Why This Is Dangerous

StealC is an information stealer sold as malware-as-a-service on criminal forums. It is designed to extract credentails from over 20 browsers and dozens of applications simultaneously. A "bonus" file in the StealC ecosystem often contains credentials from premium or financial services, making the 9,458 records in this particular upload significantly more dangerous than a standard stealer log batch. The plaintext nature of the passwords means no cracking is required.

What Was Exposed

• Email Addresses
• Plaintext Passwords
• URLs

Why This Matters

The StealC572 bonus upload represents a precision extraction of 9,458 active credentails from real devices in use at the time of infection. Each record in this log is a working login tied to a specific service. Attackers purchasing or receiving this data can immediately attempt account takeovers without any additional processing. Email address and URL combinations also allow attackers to target credential stuffing campains against specific platforms identified in the log.

How Stealer Logs Work

StealC malware is distributed through malvertising, phishing campaigns, and cracked software repositories. Once installed on a victim's device, it runs silently in the background, extracting saved passwords from browsers, session cookies, cryptocurrency wallet files, and any credentials stored in desktop applications. The data is automatically exfiltrated to the attacker's command-and-control server, packaged into log archives, and distributed through Telegram channels or sold on dark web marketplaces.

Check If You Are Affected

HEROIC's free breach scanner searches more than 400 billion exposed records, including StealC stealer logs like the 20230527_stealc572_bonus upload. Enter your email address to find out in seconds whether your credentials appeared in this breach or any other known data exposure. Acting quickly is the best way to prevent account takeover from active credential theft.