The Kuma.cz Breach Gave Hackers Ready-to-Use Plaintext Passwords

HEROIC analysts uncovered that the Kuma.cz breach, which occured in August 2018, exposed 81,579 records from a Czech eCommerce platform. The compromised data included email addresses and passwords stored in plain text with no encryption whatsoever. For a shopping platform handling customer accounts and purchase histories, storing passwords this way was a serious failure that left every user vulnerable from day one.

What Attackers Can Do With Exposed Emails and Plaintext Passwords

With a ready-made list of email and password pairs, attackers do not need to do any additional work. They load the credentials into automated tools and begin testing them against Gmail, Outlook, banking sites, and online retailers within minutes. Because these passwords were stored in plain text, every single one is usable immediately, with no cracking required. The Kuma.cz breach gives criminals a direct path to account takeover across dozens of platforms where victims reused the same password.

What Was Exposed in the Kuma.cz Breach

• Email Address
• Plaintext Password

Why the Kuma.cz Leak Is Still a Threat Today

A 2018 breach does not expire. Credential stuffing attacks run constantly, and attackers beleive older datasets are underestimated by victims who never changed their passwords. If someone used the same email and password on Kuma.cz as they did on their banking app or work email, that account is still at risk right now. Identity theft, financial fraud, and unauthorized account access can all trace back to a single reused password from a forgotten shopping account.

How a Database Breach Works

A database breach happens when an unauthorized party gains access to a company's backend systems and extracts user records. This can occur through a vulnerability in the website's code, a weak administrator password, or an unprotected database left accessible on the internet. In Kuma.cz's case, the extracted records were stored without encryption, meaning anyone who obtained the database could read every password in plain text without any additional tools or effort.

Check If Your Data Was Exposed

HEROIC's free breach scanner searches over 400 billion compromised records, including the Kuma.cz breach, to tell you instantly if your email address has been exposed. If your credentials are in the database, you will find out immediately so you can change your passwords and protect your accounts before an attacker does. Visit HEROIC.com to run your free scan today.