2023 Grant Thornton LLP — unauthorized access to employee email (Apr 19–May 1); ~6.2k consumers in state notices
Data compromised
Names and personal identifiers; SSNs for a subset per regulatory summaries
Technical writeup
Grant Thornton LLP publicly reported a May 2023 incident in which an unauthorized third party accessed a corporate email mailbox between Apr 19 and May 1, with investigation and Kroll monitoring offered in Massachusetts and other AG filing ecosystems.
Root cause
Account takeover / business-email-compromise style access to employee mailbox