6.24 Million Login Combo List Fuels Attacks Across US Services

Buried inside a batch of files labeled 17.10_18.21_88 and passed around on Telegram, researchers found a combolist holding 6,243,255 lines of email and password pairs, dated October 10, 2024. A number that large can feel abstract on a screen, but a combolist this size is basically a phonebook built for automated account takeover, assembled so criminals can run through millions of login attempts without lifting a finger themselves.

Why This Is Dangerous

A combolist is different from a raw breach dump because the credentials are already paired and cleaned up for immediate use. There's no cracking or guesswork involved, the email and password sit right next to each other in plaintext, ready to be fed straight into automated login tools. That convenience for attackers is exactly what makes a file like this so much more dangerous than scattered data floating around separately.

What Was Exposed

• Millions of email addresses tied to US accounts
• Plaintext passwords matched directly to each address
• URLs pointing to the specific services each pair unlocks

Seeing the destination URL next to each credential pair means an attacker doesn't have to guess where to try logging in, the file practically hands them the target list.

Why This Matters

Combolists like this one get pulled from a mix of older breaches, stealer logs, and phishing hauls, then merged into one giant file. If any password in here matches one you're currently using anywhere else, that seperate account becomes just as vulnerable, even if it was never part of the original leak. Attackers count on people never changing a password once it's set.

How Combolists Work

Rather than coming from a single hack, a combolist is stitched together from many smaller sources over time. Criminals compile the credentials, remove duplicates, and format everything the same way so it can be loaded directly into credential stuffing software. That software then hammers login pages with each pair at high speed, and any hit that succeeds becomes a compromised account. It's mostly automated, which is why an event like this occured with over six million entries at once.

Check If You Are Affected

The only real way to know if your login information ended up in a file like this is to check. HEROIC's free scanner searches across a database of more than 400 billion leaked records, combolists included, and tells you right away if your email shows up. If it does, updating that password everywhere you've reused it is the fastest way to close the gap.