Phone numbers and other account details for some 533 million Facebook (FB) - Get Report users has been posted on the dark web recently, reported a cyber-threat intelligence firm and several news outlets.
The information that was exposed includes profile information, Facebook identification numbers, emails, location data and more, according to a report in The Record, which is published by cyber-threat intelligence firm Recorded Future. The Record said it had made a "cursory" review of the stolen data, showing a screen grab of a forum user with an anime-style user icon announcing the data was available.
Facebook did not immediately respond to a request for comment, but told The Record that the data was old and that it "was previously reported on in 2019 ... We found and fixed this issue in August 2019.”
Still, according to the cyber security firm, the data that was stolen from users around the world was still available for download.
"There is a massive market ... for buying and selling personal records and personal information," Recorded Future's CEO Christopher Ahlberg told TheStreet on Sunday in a brief phone interview.
Even though the information was taken in 2019, much of it could still be valuable to cyber criminals, said Ahlberg.
"You don't give your Social Security number to Facebook," he said, and credit card information would be outdated by now, even if it was given. But, he said, users do often give lots of other information that would be of use, especially when combined with other hacked data.
"It's unlikely that someone is going to change their name or phone number" over the past two or three years, he pointed out.
In addition, he said, this "regurgitation" of an old, massive hack shows how vulnerable data can be once it's stolen. The reemergence of the data was also earlier reported by Business Insider, which credited Alon Gal of cyber-crime intelligence firm Hudson Rock for spotting the information on a forum.
The only way to find out that such information is posted online again, Ahlberg said, is from companies that scour the dark web for people trying to sell it.
A hacker had taken advantage of a "vulnerability" in the Facebook contacts importer feature, according to The Record, which said Facebook detected the automated process, and then plugged the hole.
Why is this news now?
"Some dude was coming out to sell this," said Ahlberg. "Somebody was selling this and what people will do is they will regurgitate old things."
This story has been updated with new information and some typos corrected.