3,749 Accounts Leaked: Inside the Hotmail Combo List Breach

On 17-Oct-2024, a Telegram user uploaded a file labeled "5k HOTMAIL COMBO," a stealer log containing 3,749 records of stolen login data. The file included email addresses, plaintext passwords, and the URLs of the websites those credentials were used on, all pulled from malware-infected devices rather than a single company's servers.

Why This Is Dangerous

A "combo list" is simply a bundle of email-and-password pairs collected for reuse by criminals, and this one carries an added risk: the passwords are stored in plaintext. That means no cracking or decryption is needed. Anyone who gets their hands on this file can start testing the logins the moment they open it.

What Was Exposed

• Email addresses
• Plaintext passwords
• URLs of the websites the credentials were used on

Why This Matters

Even at 3,749 records, a combo list like this is valuable to attackers because people so often reuse the same password across multiple accounts. Criminals feed lists like this into automated tools that try each login against email providers, banks, and social media platforms, a technique called credential stuffing. A successful match can lead directly to account takeover, identity theft, or financial fraud.

How Stealer Logs Become Combo Lists

Stealer malware infects a device through a cracked program, a fake update, or a malicious attachment, then quietly collects saved browser passwords, autofill data, and the web addresses they belong to. That raw data is sent back to whoever runs the malware and often gets cleaned up and repackaged into a "combo list," a simplified email-and-password file that's easier for other criminals to buy, trade, or use directly. The "5k" label on this file refers to the round-number batch size typically advertised by sellers, even though the actual verified count came in at 3,749 records.

Check If You Are Affected

If you have ever used a Hotmail or Outlook account, it's worth checking whether your details appear in a leak like this one. HEROIC's free breach scanner searches a database of more than 400 billion leaked records and tells you instantly if your email address has been exposed. If you get a match, change that password immediately, make sure you are not reusing it elsewhere, and turn on multi-factor authentication for extra protection.