The UP_KURZL0G Breach Put 1.2 Million Stolen Login Pairs Online

The stealer log dump known as UP_KURZL0G put 1,264,421 stolen email and password pairs online after a Telegram user uploaded it on October 18, 2025. Each record includes an email address, a plaintext password, and the exact URL of the account it belongs to. HEROIC analysts confirmed the file during routine dark web monitoring, and the numbers alone make it one of the larger stealer log dumps tracked this month.

Why the UP_KURZL0G Breach Is Dangerous

A million plus working logins in plaintext is not a theoretical risk, it is a ready to use attack kit. There is no password hash for an attacker to crack and no guessing involved, just a direct email, password, and URL match for over a million accounts. That level of accessability is exactly why stealer logs like this one move so quickly through criminal marketplaces once they surface.

What Was Exposed in the UP_KURZL0G Dump

• Email addresses linked to real accounts
• Plaintext passwords stored with zero encryption
• URLs showing exactly which site or service each login opens

HEROIC confirmed 1,264,421 total records inside the file, most connected to users in the United States.

Why This Matters for Everyone in the Dump

Files this size feed directly into credential stuffing operations, where automated tools run each stolen email and password against hundreds of other websites, hoping people reused a login somewhere else. When a match works, the attacker gains account takeover, and from there identity theft and financial fraud become very real outcomes rather than distant possibilities. The larger the dump, the more accounts get tested, and the more victims end up affected without ever noticeing it happened.

How a Stealer Log Like UP_KURZL0G Comes Together

Infostealer malware is the engine behind dumps like this. It infects a device through a fake download, a cracked program, or a phishing email, then quietly reads every saved password, autofill entry, and browsing URL straight out of the victim's browser. All of it gets bundled into a single file and shipped to the attacker, who then uploads it to Telegram channels or dark web forums under a tag like UP_KURZL0G, ready for other criminals to buy or trade.

Check If You Are Affected

With over 1.2 million records in play, the odds that your email or an old password is somewhere in the UP_KURZL0G dump are worth taking seriously. HEROIC's free breach scanner checks your information against a database of more than 400 billion leaked records and gives you an answer in seconds. Run a free scan now and update anything that comes back exposed.