CHICAGO (CBS) — The FBI and Attorney Generals from at least four states, including Illinois, are investigations the mother of all cyber attacks.

A class action lawsuit is also in the works.

Equifax, the credit bureau whose job it is to protect data, announced Thursday that 140 million people could be victims of a data breach.

RELATED: Equifax Breach Exposes 143 Million People To Identity Theft

The hackers received names, address, social security numbers and credit card numbers. CBS 2’s Mai Martinez explains what you need to know.

What should we do?

It’s the question on Robert Primm’s mind, and likely millions of other Americans, following the massive Equifax data breach.

“I was really upset because it’s one of the credit bureaus,” said Jessica Pimentel, who is concerned.

Fraud expert Bill Kresse said the cyber criminals hit the “mother load.”

“This was names, addresses, social security numbers, driver licenses, dates of birth. This is keys to the kingdom of an identity thief,” Kresse said.

“It’s a lot going on here and to compromise our personal information you know people could do anything with that information,” said Annette Newell, concerned about the Equifax breach.

Kresse said the first thing people should do is go to the Equifax website to see if they are at risk.

Next they should monitor all bank and credit card accounts for any suspicious activity; and change passwords on all accounts, making them different and complex. Finally they should subscribe to a credit protection service.

“From now on, credit protection is going to be like buying life insurance or car insurance. It’s just going to be a cost of living in the United States,” Kresse said.

On its website, Equifax is offering a year of free credit monitoring and identitiy theft protection, but Kresse cautions, that likely won’t be enough if your information has been compromised.

“You know you don’t change your birth date. You don’t change your social security number. This is something that those who have been jeopardized by this hack will have to protect themselves for years, until they are dead,” Kresse said. “If you weren’t a victim of this hack, you will be of another in the future.”

When monitoring your accounts, pay attention to even the smallest debit or credit because that could actually be a “test transaction,” criminals are using to see if that have access to your accounts.