Hackers accessed data belonging to approximately 8.7 million customers of Manchester, London Stansted and East Midlands airports in a ransomware attack on Manchester Airports Group (MAG).
The stolen information mainly consisted of email addresses provided by passengers when registering for airport Wi-Fi. A smaller proportion included names, postal addresses, telephone numbers, postcodes and vehicle registrations linked to bookings for parking, airport lounges and fast-track security services.
MAG stressed that the affected system contained no banking or payment-card information. Passenger safety, airport operations and aviation security were not compromised.
The group became aware of the intrusion on Tuesday and said it quickly contained the breach, preventing the attackers from obtaining further access. The hackers subsequently demanded a ransom for the return of the data, but MAG refused to pay. The amount demanded was not disclosed.
Affected customers have been notified, while the relevant authorities and specialist cybersecurity advisers are investigating. MAG said it knows the identity of the group responsible, although it has not publicly named the attackers.
Customers have been advised to watch for phishing attempts, including suspicious emails, text messages and telephone calls, and not to open links or attachments from unknown senders.