The ARCEUSULP 121 Data Just Went Public on the Dark Web

HEROIC analysts identified this stealer log on 20-Jun-2026. The breach exposed 82,988 records, with stolen data including email addresses, plaintext passwords, and URLs. The source is identified as ARCEUSULP 121.

Why This Is Dangerous

With plaintext passwords and email addresses in hand, attackers can immediately attempt to log into email accounts, social media profiles, banking portals, and any other service where the victim reuses the same password. Because these passwords are not encrypted or hashed, no cracking is required. The URLs in this dataset also reveal exactly which websites the victims were using, giving attackers a ready-made list of targets to try.

What Was Exposed

• Email Addresses
• Plaintext Passwords
• URLs

Why This Matters

Stealer log data like this is traded and sold in private cybercriminal communities. Once your email and password appear in a leak like ARCEUSULP 121, they can be used in credential stuffing attacks, where automated tools try your stolen login across dozens of websites at once. A single successful login can lead to account takeover, financial fraud, or identity theft. Because the passwords are in plaintext, there is no technical barrier for attackers.

How a Stealer Log Works

A stealer log is a file produced by a type of malware called an information stealer. This malware infects a device silently, often through a malicious download or phishing link. Once installed, it harvests saved passwords, browser session data, and account credentials before sending them to the attacker. The resulting file is then shared in private channels where other criminals can download and use the stolen data.

Check If You Are Affected

HEROIC offers a free breach scanner that searches 400 billion records from known breaches. Search your email address now to find out if your credentials appear in this breach or others. The scan is free and takes seconds.