Following record results that flagged the growth of its cybersecurity business, Deloitte has revealed that it has been successfully targeted by a cyberattack that let hackers access data from an internal e-mail platform.

The auditing and consulting firm said in a statement on Monday that it’s currently informing the clients affected and has notified governmental authorities after it became aware of the incident.

Deloitte said “very few” clients were impacted, and has drafted outside help to review its security. The hack was first reported by The Guardian.

The e-mail platform was stored on Microsoft’s Azure cloud platform, according to The Guardian. A spokeswoman from Microsoft declined to comment.

The UK-domiciled firm offers a range of consultancy services to blue-chip clients, and earlier this month posted record revenues of US$38.8bn for the financial year ended 31 May. Deloitte flagged that its Risk Advisory business has seen increasing demand for cybersecurity advice, and the company had launched a number of Cyber Intelligence Centres that offer clients constant threat analytics and management.

Although nowhere near the same scale, the hack follows the infiltration of Equifax, where attackers accessed personal data for as many as 143m US consumers.

Regulators are facing their own challenges in their attempts to monitor hacks. The US Securities and Exchange Commission this month disclosed that cybercriminals breached its online database of corporate filings, but they may have stolen corporate secrets that they profited from. — Reported by Giles Turner, (c) 2017 Bloomberg LP