Analysts Find ARCEUSULP 122 Stealer Log With 341,454 Logins

HEROIC Analysts Uncover the ARCEUSULP 122 Stealer Log

On June 20, 2026, HEROIC analysts discovered a stealer log file, labeled "ARCEUSULP 122 843698," circulating through a Telegram channel. The file contained 341,454 records, each pairing an email address with a plaintext password and the web address the credential was used on. The unusual filename is typical of stealer logs, which are often named and numbered by the malware operators who generate and catalog them in bulk before distribution.

Why This Is Dangerous

Every password in this file is stored in plaintext, meaning it can be read and used instantly by anyone who obtains the log, without needing to crack or decrypt anything. Because each entry also lists the exact site the login belongs to, attackers can quickly sort the data by target, whether that is email providers, retail accounts, or financial platforms. With over 341,000 entries, this log gives criminals a substantial pool of working credentials to test at scale.

What Was Exposed

• Email addresses
• Plaintext passwords
• Website login URLs tied to each credential

Why This Matters

Stolen logins rarely stay limited to the one account they were captured from. Because password reuse is so common, a single leaked credential can unlock several other accounts belonging to the same person. Criminals typically feed large stealer logs like this one into automated credential stuffing tools that attempt each email and password pair across many popular websites at once, looking for any match that leads to account takeover, financial fraud, or identity theft.

How Stealer Logs Work

This file is the product of infostealer malware, which infects a device, usually through a malicious download or phishing link, and then silently extracts saved credentials from the victim's web browser. The malware packages everything it finds, sometimes including cookies and autofill data, into a log file that gets sent back to the attacker. Operators then organize these logs, often naming and numbering them as batches, before uploading them to Telegram channels or dark web marketplaces where other criminals can access them.

Check If You Are Affected

Given the scale of this log, checking your exposure is a smart first step. HEROIC's free breach scanner searches more than 400 billion leaked records, including stealer logs like ARCEUSULP 122, to show you if your email address has been compromised. Run a free scan, and if you find a match, change that password immediately and enable multi-factor authentication on any account where it is available.