533 million Facebook users' phone numbers and personal data leaked online on Saturday

A user in a low level hacking forum on Saturday published the phone numbers and personal data of hundreds of millions of Facebook users for free online.

The exposed data includes personal information of over 533 million Facebook users from 106 countries, including over 32 million records on users in the US, 11 million on users in the UK, and 6 million on users in India. 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.

"A database of that size containing the private information such as phone numbers of a lot of Facebook's users would certainly lead to bad actors taking advantage of the data to perform social engineering attacks [or] hacking attempts," Gal told Insider.