If you are reporting on or responding to the discovery of such a file, follow these industry-standard security practices:
An "Email Combo zip" typically refers to a : a compressed file containing large sets of stolen email and password pairs. These files are often aggregated from various data breaches and circulated on dark web forums or messaging apps like Telegram to facilitate credential stuffing attacks. Key Findings on Email Combo Files
Hackers use automated tools to "stuff" these credentials into other websites, hoping users have reused the same password across multiple accounts.
Dark Web Combo Lists: How to Detect Leaked Credentials - Breachsense
Organizations should use dark web monitoring services, such as those provided by Aura or Proton , to receive alerts when company credentials appear in new combo files.
Use tools like Have I Been Pwned to check if specific email addresses have been included in known "combo" breaches.