Users could be found on Facebook for a long time by entering a phone number. The feature was shut down last spring after Facebook acknowledged that it had been misused for data tapping.
This is not the topic from the world, as the discovery of a security researcher reveals: he has found on the Internet an accessible database with entries for hundreds of millions of Facebook users. According to the TechCrunch magazine the researcher turned to, it contained the phone numbers of more than 419 million social network users.
The database appears to have been compiled by misusing the friend search feature by phone number. However, anyone who has collected and uploaded the data for what purpose is unclear. Meanwhile, the database is no longer in the network, they say.
Facebook said on Wednesday that it was old data. They were probably gathered before the network shut down the possibility last year to find acquaintances using their phone numbers. Facebook has no evidence that accounts have been hacked.
Many users from the US are affected
The telephone numbers are each linked to the Facebook identification number, which allows profiles to be found independently of changes to the user name. According to TechCrunch, 133 million phone numbers are from Facebook users in the US, 18 million from the UK and more than 50 million from Vietnam.
In some cases, information on the name and gender of the users had been included, they say. For example, criminals could misuse the numbers from the database to reset passwords for Facebook accounts and hijack the profiles. Likewise, the numbers could be used for spam calls or phishing attacks.
Although the phone numbers were not publicly visible on Facebook itself, they could possibly be accessed via automated queries - so-called "scraping" - on a large scale. Although this violated the rules of the network in principle, it was technically possible. Facebook is also struggling with the scraping of publicly available profile data on its Instagram photo platform.