Global accounting firm Deloitte said on Monday it was the victim of a cyber attack that affected the data of a small number of clients, providing few details on the breach.
Deloitte said in a statement that attackers accessed data from the company’s email platform, confirming some details in a report by the Guardian newspaper, which broke news of the hack on Monday.
The attack appeared to target the firm’s U.S. operations, was discovered in March and could have begun as early as October 2016, according to the Guardian. Deloitte’s statement did not confirm those details.
The breach at Deloitte, which says its customers include 80 percent of the Fortune 500, is the latest in a series of breaches involving organizations that handle sensitive financial data that have rattled lawmakers, regulators and consumers.
The U.S. Securities and Exchange Commission, Wall Street’s top regulator, and Equifax Inc (EFX.N), one of the largest credit-monitoring bureaus, this month reported that confidential filings and sensitive personal data were compromised by hackers.
“These are targeted attacks on financial opportunity,” said Shane Shook, an independent consultant who helps financial firms investigate cyber attacks. “This trend is going to continue to grow.”
The firm said it contacted government authorities immediately after it became aware of the incident, and notified each of the “very few clients” that had been affected.