Our Analysts Found the Cit0day Compilation Circulating on Hacking Forums

HEROIC analysts found the Cit0day compilation circulating across multiple hacking forums in November 2020, where it was being shared and traded at scale. The dataset exposed 196,737 accounts in the cit0day.in domain alone, containing email addresses and plaintext passwords harvested from a collection of breached websites that had been quietly aggregated over time.

Why Plaintext Passwords Make the Cit0day Breach Immediately Exploitable

Unlike breaches that expose only hashed passwords, the Cit0day compilation included plaintext password pairs that are accessable to any attacker without any cracking step. This means the credentials are ready for immediate use in credential stuffing attacks, allowing automated tools to test them across email providers, banking platforms, and other online services within hours of obtaining the data.

What Was Exposed in the Cit0day Breach

• Email Address
• Plaintext Password

Why a Forum-Based Credential Compilation Like Cit0day Represents a Lasting Threat

The Cit0day data occured in a context where multiple previously undisclosed breaches were combined into a single package and distributed broadly. Because the compilation drew from many seperate sources, affected users may not have recieved notification from any specific breached service, leaving their credentials actively circulating without their knowledge. This makes periodic breach monitoring essential for anyone who has used email-based logins over the past several years.

How a Database Breach Works

In a database breach, attackers gain unauthorized access to backend data stores through vulnerabilities in web applications, server misconfigurations, or compromised admin credentials. In compilation cases like Cit0day, data from many individual breaches is aggregated and cross-referenced, creating a single dataset that is far more useful to attackers than any individual source alone.

Check If Your Data Was Exposed

HEROIC's free breach scanner searches over 400 billion records to tell you instantly whether your email address and password appeared in the Cit0day compilation or any other known breach. Run a free scan at HEROIC.com to find out what credentials of yours are exposed and take action before attackers do.