How ARCEUSULP Malware Leaked 313,502 Emails and Passwords

ARCEUSULP 258 981688 Stealer Log: 313,502 Records Exposed

On 20-Jun-2026, HEROIC analysts uncovered a file named "ARCEUSULP 258 981688" posted by a Telegram user trading in stolen credentials. The file held 313,502 records, each combining an email address, a plaintext password, and the URL of the site the login was captured from. That scale makes this one of the larger stealer log dumps HEROIC has cataloged from this Telegram source in recent months.

Why This Stealer Log Is Dangerous

The danger here comes from the combination, not just the size. Every record pairs a working password with the exact website it unlocks, so an attacker can move straight from the file to logging into a real account without any extra guesswork. With plaintext passwords and over 313,000 records to work through, automated tools can process the entire file and attempt logins across many sites in a very short amount of time.

What Was Exposed

• Email addresses
• Plaintext passwords
• URLs of the sites the credentials were used on

Why This Matters

A leak of this size means credential stuffing attacks become far more efficient for whoever obtains the file, since attackers can run hundreds of thousands of login attempts against banking, email, and shopping accounts using pairs that are already known to work on those exact sites. Anyone reusing a password across accounts is at heightened risk of account takeover, and any personal or financial details reachable through those accounts are effectively exposed as well.

How Stealer Logs Work

Stealer logs are built by malware that infects a victim's device, usually through a malicious download, cracked software, or phishing link, and then silently copies saved browser logins, passwords, and the websites they belong to. That harvested data gets compiled into a log file like this one and distributed through Telegram channels and dark web marketplaces, where it can be bought, sold, or shared among other cybercriminals.

Check If You Are Affected

With more than 313,000 records in this single file, it is worth checking your exposure directly rather than assuming you are not affected. HEROIC's free breach scanner checks your email against a database of over 400 billion leaked records, including stealer logs like this one, so you can quickly find out and secure any accounts that may be at risk.