About 607,000 DfE records were taken in a cyber-attack, with exposed data limited to phone numbers and email addresses tied to individuals and organisations.
The department said the breach was contained quickly, no bank details or other sensitive data were accessed, and the risk to individuals is not considered high.
The Turing Scheme portal and the DfE online help desk were affected, though both are expected to return to normal operation later this week.
The DfE is working with the National Cyber Security Centre and National Crime Agency, and has referred itself to the Information Commissioner's Office.
The breach lands amid rising attacks on education bodies: 24% of further education institutions report weekly incidents, and more than half of schools faced a breach in the past year.