Hackers leveraged a security flaw in a tool designed to build web applications to steal customer data. Equifax admitted it was aware of the security flaw a full two months before the company says hackers first accessed its data.

The data breach prompted the resignation of CEO Richard Smith and investigations by federal regulators, multiple states attorneys general and the company faces a number of civil lawsuits.

Bill Evanina, the director of the National Counterintelligence and Security Center, told reporters Monday that the Equifax hack reflects the type of "consistent, persistent and unacceptable" activity from China that has been observed over the last year -- posing a significant counterintelligence threat to the US.

Foreign adversaries -- and China in particular -- continue to target the US private sector to steal personal data and trade secrets in a way that reflects the broader need to for a "systemic change" in the way American companies and the public view those threats, Evanina said, adding that attacks like the one on Equifax must be viewed as a counterintelligence issue rather than just a cyber threat.

"Equifax has all of your data and Americans should care about that," Evanina said.

That data is being used by foreign intelligence services for many purposes, including to enhance their country's artificial intelligence capabilities -- a goal that requires a much information as possible, he warned.

A major concern, according to Evanina, is China's targeting of Americans, particularly government officials who do not possess a security clearance, by using data of this nature to identify potential vulnerabilities and using that information as leverage for their own purposes.

"Today we saw yet another indictment of the Chinese military for targeting the US private sector, highlighting their long-term effort to undermine US economic competitiveness and our strategic position globally," said Jamil N. Jaffer, senior vice president for strategy, partnerships & corporate development at IronNet Cybersecurity.

"This intentional data theft is part of a larger Chinese effort to go after US companies, and it is therefore critical that American and allied companies work with one another -- and across industries -- to collectively defend themselves against this committed threat actor," said Jaffer, who also previously served as the chief counsel and senior adviser to the Senate Foreign Relations Committee and currently serves as founder and executive director of the National Security Institute at GMU Law School.

This story has been updated to reflect additional information and Barr's comments.