ARCEUSULP Stealer Log Discovered: 397,873 Logins Leaked

In June 2026, a stealer log file named "ARCEUSULP 143 781871" was discovered circulating on a Telegram channel used to trade stolen login data. Inside were 397,873 sets of credentials, email addresses, plaintext passwords, and the URLs of the accounts they unlock, all harvested from devices infected with information-stealing malware.

What Turned Up Inside the ARCEUSULP Log

A closer look at the file revealed nearly 400,000 individual credential pairs, far larger than the average stealer log traded on Telegram. Each row followed the same pattern: an email address, a password sitting in plain text, and the exact web address the login opens. That structure is what makes stealer logs so easy for criminals to weaponize, there is no decryption step standing between discovery and misuse.

What Was Exposed

• Email addresses
• Plaintext passwords
• URLs of the accounts and websites those logins access

Why This Matters

With 397,873 plaintext logins in a single file, the risk of credential stuffing rises sharply. Automated tools can test every one of these email and password pairs against major email providers, banks, and online stores within hours. Anyone in this log who reused a password elsewhere faces a real chance of account takeover, and depending on which accounts are affected, identity theft or financial fraud can follow quickly.

How a Log This Large Gets Assembled

Stealer logs of this size are typically built from information-stealing malware running across many infected devices at once. Victims are usually infected through pirated software, cracked games, or malicious downloads, and the malware quietly copies every saved password, along with the site each one belongs to, before sending it back to the attacker. Operators then merge output from multiple infections into a single combined file, which is how a log can grow to hundreds of thousands of records before it ever reaches Telegram.

Check If You Are Affected

With nearly 400,000 records involved, checking your exposure only takes a moment. HEROIC's free breach scanner compares your email against more than 400 billion leaked and breached records, including stealer logs like this one, and tells you right away if you show up. If you do, change the exposed password immediately, update it anywhere else you used it, and turn on two-factor authentication wherever it is available.