SITA provides IT services to about 90% of the global aviation industry. Finnair, Finnair and Singapore Airlines are among those who have acknowledged that passenger data from their frequent flyer programs was breached in the incident. British Airways Executive Club Members’ names, membership numbers and some of their preferences, such as seating, has been impacted. Passwords and financial information have not been exposed by the security breach, but frequent flyer membership numbers, passenger names, and itineraries may all now be in the hands of criminals.”]
Source: https://grahamcluley.com/airline-passenger-data-breached-following-highly-sophisticated-attack/