Hold Security is a firm that works to uncover online security breaches and help prevent them.
And they say this is the largest breach ever.
This heist is affecting 420,000 websites.
The breach comes right as parents begin back to school shopping sprees online.
Experts say you don't have to abandon the internet, but be careful about where you're shopping.
"Using credible, for lack of a better word, retailers is the best thing you can do,” said Dennis Horton, the director of the Better Business Bureau Rockford.
The spokesperson for Fat Wallet, Brent Shelton, offers the following advice to internet users:
1.Change passwords frequently (especially for financial, health and credit accounts, and after a hack of this proportion)
2.Limit places you provide personal information.
3.Use an online payment service (like PayPal, or FatWallet Checkout to help you avoid creating multiple accounts/passwords)
4.Create strongest passwords (especially for the sites that contain the most sensitive information)
5.Do not reuse passwords for different accounts
6.Enable secondary authentication (when available)
7.Password Managers (like LastPass or Password Safe help you create unique passwords for individual accounts, reducing the risk of reused passwords or ones easy to decode)
The BBB is actively investigating this hacking event.
Copyright 2015 Nexstar Broadcasting, Inc. All rights reserved. This material may not be published, broadcast, rewritten, or redistributed.