Phone numbers of 420 million Facebook users in online database

5. September 2019

A database with more than 400 million phone numbers of Facebook users was publicly accessible online. Most of the records belong to American Facebook users (133 million), 50 million to users from Vietnam and 18 million to users from the UK. In each case the phone number was connected with the user’s Facebook ID, a long, unique and public number associated with the account.

As a result of the publicly accessible data the concerned users are put at risk for spam calls and SIM-swapping attacks. Furthermore, the passwords of the accounts can be changed so that the user cannot access his own Facebook profile.

IT-expert Sanyam Jain found the database and contacted TechCrunch after being unable to find the owner. TechCrunch verified the authenticity of the found data and then tried to determine the owner – without success. So they contacted the web host who turned the site down.

The database is not accessible at the moment, but it is still unknown how the data was collected and who uploaded the information. It is possible, that the ability to find friends by phone number on Facebook was misused to create the database. This feature was disabled by Facebook in April 2018. In connection to this new infringement, Facebook just announced that there is no evidence for a hacking attack.

Update: on Friday September 6th 2019 a copy of the database appeared on the internet, so that the data is currently publicly accessible again.