REUTERS

A user in a fringe hacking forum on Saturday published a trove of phone numbers and personal data of hundreds of millions of Facebook users for free.

The exposed data includes personal information of over 533 million Facebook users from 106 countries, Business Insider reports.

It includes their phone numbers, Facebook IDs, full names, locations, birthdates, bios, and – in some cases – email addresses.

Insider reviewed a sample of the leaked data and verified several records by matching known Facebook users' phone numbers with the IDs listed in the data set. We also verified records by testing email addresses from the data set in Facebook's password reset feature, which can be used to partially reveal a user's phone number.

A Facebook spokesperson told Insider that the data was scraped due to a vulnerability that the company patched in 2019.

While a couple of years old, the leaked data could provide valuable information to cybercriminals who use people's personal information to impersonate them or scam them into handing over login credentials, according to Alon Gal, CTO of cybercrime intelligence firm Hudson Rock, who first discovered the entire trough of leaked data online on Saturday.

Read also9News Australia sees massive cyber attack amid work on episode on PutinNow, the entire dataset has been posted on the hacking forum for free, making it widely available to anyone with rudimentary data skills.

This is not the first time that a huge number of Facebook users' phone numbers have been found exposed online. The vulnerability that was uncovered in 2019 allowed millions of people's phone numbers to be scraped from Facebook's servers in violation of its terms of service. Facebook said that vulnerability was patched in August 2019.

Facebook previously vowed to crack down on mass data-scraping after Cambridge Analytica scraped the data of 80 million users in violation of Facebook's terms of service to target voters with political ads in the 2016 election.