We're tracking emerging information on what could be the biggest exposure ever of personal information.

I'm David Brancaccio. It's emerged that hackers may have gotten their hands on personal information of most of America.

This includes Social Security numbers, many possibly all Social Security numbers.

Details remain sketchy about this hack from the spring, but according to a court filing and cybersecurity

researchers, this involves a firm that does background checks that contained nearly 3 billion

records. Marketplace's Novaosafo has more.

The breach was first spotted in April when the stolen data was put up for sale for about 3.5 million dollars,

according to the cybersecurity firm Hackmanac.

Then that data appears to have been dumped online and when checked, some of it at least

appeared to be authentic social security numbers according to multiple reports. But it's unclear if all of the

data is authentic. How much of it is duplicative or whether at least some of it was gathered

from publicly available information online.

Neither the Social Security Administration nor the background check company that may

have been breached called National Public Data have commented.

The company is the subject of a proposed class action lawsuit filed earlier this month in which the lead plaintiff says his data was compromised.

Experts say many Americans personal information has already likely been compromised in various breaches.

As protection, they recommend freezing credit files with the three major reporting agencies

and using two-factor authentication whenever possible, as opposed to just a single password.

I'm Nova Sophop for marketplace.

In all those packs of apologies we now get in the mail regularly, we're so sorry your data was

hacked but we've arranged for you to sign up for

three months of credit monitoring. I know someone who got three from three different companies

...