The hacker compromised the firm’s global email server through an “administrator’s account” that, in theory, gave them privileged, unrestricted “access to all areas”.
The account required only a single password and did not have “two-step“ verification, sources said.
Emails to and from Deloitte’s 244,000 staff were stored in the Azure cloud service, which was provided by Microsoft. The hackers had potential access to usernames, passwords, IP addresses, architectural diagrams for businesses and health information. Some emails had attachments with sensitive security and design details.
The source told KrebsOnSecurity they were coming forward about the breach because, “I think it’s unfortunate how we have handled this and swept it under the rug. It wasn’t a small amount of emails like reported. They accessed the entire email database and all admin accounts. But we never notified our advisory clients or our cyber intel clients.” “Cyber intel” refers to Deloitte’s Cyber Intelligence Centre, which provides 24/7 “business-focused operational security” to a several big companies, including CSAA Insurance, FedEx, Invesco, and St. Joseph’s Healthcare System, among others. This same source said forensic investigators identified several gigabytes of data being exfiltrated to a server in the United Kingdom. The source further said the hackers had free reign in the network for “a long time” and that the company still does not know exactly how much total data was taken.