If You Reuse Passwords, the 500K Hotmail Leak Should Worry You

HEROIC analysts found a combolist named "500k HQ Hotmail Combo Test professor66699" that a Telegram user uploaded on 29-Oct-2024. The file contains 536,588 records of email and username and password credentials, largely tied to Hotmail accounts in the United States.

Why This 500K Hotmail Leak Is Dangerous

At over half a million records, this combolist gives an attacker an enormous, ready-to-use list of email and password pairs. There is no cracking involved, the passwords are stored in plaintext, so anyone who gets a copy of the file can start testing the credentials against other websites immediately.

What Was Exposed

• Email Addresses
• Plaintext Passwords
• URLs

Why This Matters

If you reuse passwords across different accounts, a leak of this scale should worry you. With 536,588 credential pairs circulating, attackers can run large-scale credential stuffing campaigns against banking, shopping, and social media platforms. Because Hotmail accounts are frequently used to reset passwords elsewhere, a compromised email login can quickly turn into account takeover, financial fraud, or identity theft across multiple services.

How a Combolist of This Size Comes Together

Large combolists like this one are usually built by merging credentials from several older breaches, phishing operations, and infected devices into a single file over time. Once a Telegram user uploads a combolist of this size, it circulates quickly, giving a large number of attackers access to the same list of working logins.

Check If You Are Affected

With more than half a million records involved, checking your exposure now is a smart move. HEROIC's free breach scanner searches a database of more than 400 billion leaked records, including combolists like this one, so you can quickly find out if you're affected and update any passwords that need it.