Around 8.7 million customers across MAG's three airports – Manchester, Stansted and East Midlands – have been affected. The compromised data relates to customers who had used in-airport WiFi or made bookings for car parking, airport lounges or Fast Track security services.
Information obtained include email addresses, phone numbers, vehicle registrations and post codes, although MAG has confirmed none of the systems that were accessed hold customers' bank or payment details.
"We immediately contained the risk and have been working with specialist advisors and taking appropriate steps to protect our customers and systems," said MAG in a statement.
