Facebook announced on Friday that it has suffered a data breach affecting up to 50 million users.
According to a report from the New York Times, Facebook discovered the attack on Tuesday and have contacted the FBI.
The exploit reportedly enables attackers to take over control of accounts so, as a precaution, the social network has automatically logged out more than 90 million potentially compromised accounts.
Attackers exploited vulnerabilities in the code for Facebook’s “View As” feature, enabling them to abscond with access tokens (think fancy, security-based cookies) which could then be used to hijack the target account.
Facebook announced on Friday that it patched the vulnerability on Thursday night, disabled View As and reset the access tokens for the 50 million accounts it knows were targeted as well as another 40 million people who have used View As since its implementation last year, for good measure.
“This attack exploited the complex interaction of multiple issues in our code,” Guy Rosen, VP of Product Management, wrote. “It stemmed from a change we made to our video uploading feature in July 2017, which impacted ‘View As.’
The attackers not only needed to find this vulnerability and use it to get an access token, they then had to pivot from that account to others to steal more tokens.”
“There’s no need for anyone to change their passwords,” he continued.
With the investigation still in its early stages, neither Facebook nor law enforcement know yet who is behind the attack, where the attacks originated from, or whether any personal data was accessed. We’ll continue to update this story as developments unfold.