eFNN Data Breach Exposes 56,261 South Korean Fiber Networking Portal Accounts

HEROIC's DarkHive intelligence system discovered the eFNN data breach, exposing 56,261 records in August 2018. eFNN is the online portal for Fiber and Networking CO LTD, a South Korean fiber optics company, serving Korean-language users with news and information about fiber networking products and services. The compromised data included email addresses and plaintext passwords, putting registered users at immediate risk of credential-based attacks.

Why This Is Dangerous

Corporate portals for technology companies often attract industry professionals, B2B customers, and technical staff who use these accounts to access product information, technical resources, and business services. Plaintext password storage represents a complete security failure that gives attackers immediate, ready-to-use credentials requiring no cracking or decryption. Korean technology industry users whose eFNN credentials were exposed face account takeover risks across business email systems, corporate platforms, and any other services where they reused the same password.

What Was Exposed

• Email Address
• Plaintext Password

Why This Matters

With over 56,000 records exposed in plaintext format, the eFNN breach provides attackers with an immediately usable credential dataset targeting the South Korean fiber optics and networking industry. Business-to-business technology portals often have users with elevated access to corporate systems, partner networks, and supplier platforms, making the compromise of even a small percentage of exposed credentials potentially high-value. Credential stuffing attacks using this data can compromise corporate email accounts, leading to business email compromise fraud and supply chain attacks.

How Database Breaches Work

A database breach occurs when attackers exploit security vulnerabilities in corporate portal code, server configurations, or outdated web frameworks to gain unauthorized access to stored user data. Corporate website portals for technology companies may not prioritize security investment in the same way their core networking products do. Storing user passwords in plaintext rather than using cryptographic hashing is a fundamental security failure that means any database access immediately exposes all user credentials. Attackers export and distribute the data through dark web channels and underground markets.

Check If You Are Affected

HEROIC offers a free identity scanner searching over 400 billion records including data from the eFNN breach. Visit heroic.com to check if your information was exposed.