Almost 20% of the 2.3 billion Facebook users were exposed when the databases that were unprotected and containing the records of 419 million Facebook users were violated.

These databases were on a server that did not have protection or password, which made them free of access for anyone with an Internet connection.

Within these databases were records of 133 million users in the United States, 18 million in the United Kingdom and 50 million records in Vietnam. Each of these records contains a unique Facebook user ID and the phone number on the account, as well as containing the user's name, gender and location of the users' country.

When TechCrunch contacted Facebook to comment on the databases discovered, Facebook said: “This data set is old and seems to have information obtained before making changes last year to eliminate people's ability to find others using their numbers of phone."

It is currently unknown who was the owner of these databases, which although they were already removed from the server, the data set could be easily violated.

Even so, the massive leakage of 419 million phone numbers from Facebook users presents an incredible security risk for those users. SIM hacking is becoming a more common way of targeting users for identity theft, and all that a bad actor needs is a person's phone number and some basic information that can be obtained from engineering Social.

In addition, leaked phone numbers also expose 419 million people to potentially more spam calls.