381,699 Plaintext Passwords From the UP_KURZL0G Premium Database Just Surfaced on Telegram

HEROIC analysts identified the URL NEW PREMIUM DATABASE UNRAPPED UP_KURZL0G 19-10-2025 stealer log in October 2025, uploaded to Telegram by an anonymous threat actor advertising the collection as a premium credential database. The archive contained 381,699 records with email addresses, plaintext passwords, and the URLs of the services each victim used. Marketed as "premium" on underground channels, this type of curated stealer log commands attention because the credentials it contains tend to be fresher and more targeted than bulk dumps.

Why the UP_KURZL0G Premium Database Poses an Immediate Threat

The "premium" label on stealer logs like this one typically indicates that the credentials have been filtered for quality, removing duplicates and inactive accounts. Attackers purchasing or downloading this dataset receive a pre-screened list of 381,699 active email and password pairs, each linked to a specific URL. Because the passwords are in plaintext, there is zero delay between obtaining the file and beginning automated login attempts against banking sites, email providers, and corporate systems.

Data Exposed in the UP_KURZL0G Premium Stealer Log

• Email addresses (used to identify and target specific individuals)
• Plaintext passwords (no decryption or cracking needed)
• URLs (pinpoints which services and platforms each credential belongs to)

Attack Paths Enabled by This Credential Dataset

• Credential stuffing: Automated tools cycle through all 381,699 pairs against major platforms within hours
• Account takeover: Direct authentication to email, banking, and social accounts with captured logins
• Identity theft: Email plus URL data exposes which financial and government services victims used
• Financial fraud: Access to e-commerce and payment accounts enables unauthorized transactions immediately

What Makes UP_KURZL0G Stealer Logs Different From Traditional Breaches

Traditional data breaches occur when attackers compromise a company's servers and extract stored user records. Stealer logs like UP_KURZL0G work differently: the malware infects individual devices and extracts credentials directly from the browser's saved password store, capturing credentials for every site the victim visits. This means a single infected device can contribute credentials to dozens of different services simultaneously. The malware, once deployed through phishing emails or software cracks, operates silently in the background, capturing new logins in real time. The resulting logs are often labeled and sold as premium products when they contain high volumes of US or European accounts tied to financial services. Victims have no notifikation system alerting them their browser passwords were harvested, which makes timley detection almost imposible without external monitoring.

Find Out If Your Email Is in the UP_KURZL0G Premium Database

HEROIC's free breach scanner covers more than 400 billion compromised records, including stealer log collections marketed as premium databases on dark web channels. Enter your email address to check whether your credentials appeared in this dataset and get clear steps to lock down your accounts before they are accessed by someone else.