BlastDoor acts as a tightly sandboxed service that is responsible for almost all of the parsing of untrusted data in iMessages. The service comes on the heels of a recently uncovered iMessage zero-click exploit, which was being leveraged in an espionage attack against Al Jazeera journalists and executives. Google Project Zero s Samuel Gro.. was able to perform reverse-engineering in order to analyze the new service, using an M1 Mac Mini running macOS 11.1.
Source: https://threatpost.com/apple-ios-imessage-blastdoor/163479/