Security News > 2020 > April > 309 million Facebook users’ phone numbers found online
The records held Facebook users' IDs, which are unique, public numbers associated with specific accounts that can be used to figure out an account's username and other profile info.
The initial breach exposed 267,140,436 records of what were mostly Facebook users in the US. Diachenko said that all of the records seemed to be valid.
Comparitech said that 25 million of the new records contained similar information: Facebook IDs, phone numbers, and usernames.
Both Cyble researchers and Diachenko aren't sure how the breach happened, but both suggest that it could have been a hole in Facebook's third-party developer API that existed before the platform restricted access to phone numbers.
Or which lets crooks get at our user IDs and phone numbers even after Facebook restricted that access in the API. Both Cyble and Diachenko say that alternatively, the records might have been harvested by scraping, which is a good reason why you might want to rethink how much data you're publicly sharing on Facebook.