A massive Equifax data breach was announced yesterday, which ranks as one of the largest data breaches of 2017. Approximately 143 million consumers have been impacted and had their sensitive data exposed and potentially stolen.

A data breach at any company can cause considerable fallout, although this incident is particularly bad news for a credit reporting agency. Equifax aggregates and stores vast quantities of highly sensitive consumer data that are used by financial firms to make decisions about the creditworthiness of consumers. The data breach is sure to damage trust in the company.

Ironically, Equifax offers credit monitoring and identity theft protection services to companies that experience data breaches to help them protect breach victims. Naturally, all Americans affected by the Equifax data breach will be offered those services free of charge. In fact, Equifax has gone further by agreeing to offer those services free of charge to all U.S. consumers for a period of one year, even if they were not directed affected by the breach.

Chairman and Chief Executive Officer, Richard F. Smith, said “This is clearly a disappointing event for our company, and one that strikes at the heart of who we are and what we do. I apologize to consumers and our business customers for the concern and frustration this causes.”

The Equifax data breach may not be the largest data breach of 2017, but the nature of the datya exposed make it one of the most serious. Highly sensitive data were exposed, including personal information, Social Security numbers, birthdates, driver’s license numbers, and 209,000 consumers had their credit card numbers exposed.

These are the exact types of information used by cybercriminals to commit identity theft and fraud. Dispute documents were also stored on the compromised system. Those documents contained a range of personal information of 182,000 consumers. The bulk of the data related to U.S citizens, although some consumers in Canada and the United Kingdom have also been affected by the Equifax data breach.

The hacker(s) responsible for the attack had access to Equifax’s systems for a considerable period of time before the breach was discovered. Access was first gained to systems in mid-May and continued until July 29, 2017 when the breach was discovered.

According to a statement released by Equifax yesterday, hackers gained access to its systems by exploiting a website vulnerability. While sensitive data were exposed and potentially stolen, Equifax reports that its core databases that are used for credit referencing purposes, were not compromised at any point.

The data breach is still being investigated and a third-party cybersecurity firm has been hired to assist with the investigation. Smith said, “I’ve told our entire team that our goal can’t be simply to fix the problem and move on. Confronting cybersecurity risks is a daily fight. While we’ve made significant investments in data security, we recognize we must do more. And we will.”

Breach notification letters are being sent to some, but not all, breach victims. Only the 391,000 individuals whose credit card numbers or dispute documents were exposed will receive notifications by mail. All other individuals will have to check an online tool to find out if their information was exposed in the breach.