Facebook: Access tokens of 50 million accounts stolen
SAN JUAN – Facebook’s vice president of product management, Guy Rosen, said Friday that on Sept. 25, a security issue affecting almost 50 million accounts was discovered.
Although the investigation is still in its early stages, it’s clear attackers exploited a vulnerability in Facebook’s code that impacted “View As”, a feature that lets people see what their own profile looks like to someone else. This allowed them to steal Facebook access tokens which they could then use to take over people’s accounts. Access tokens are the equivalent of digital keys that keep people logged in to Facebook so they don’t need to re-enter their password every time they use the app.
Among the actions taken, the social media giant mentioned fixing the vulnerability and informing law enforcement.
It also reset the access tokens of the almost 50 million accounts “we know were affected to protect their security. We’re also taking the precautionary step of resetting access tokens for another 40 million accounts that have been subject to a ‘View As’ look-up in the last year. As a result, around 90 million people will now have to log back in to Facebook, or any of their apps that use Facebook Login. After they have logged back in, people will get a notification at the top of their News Feed explaining what happened,” Rosen wrote.
The “View As” feature is also being “temporarily” turned off while the company conducts “a thorough security review.”
The attack exploited the “complex interaction of multiple issues in our code. 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.
“Since we’ve only just started our investigation, we have yet to determine whether these accounts were misused or any information accessed. We also don’t know who’s behind these attacks or where they’re based. We’re working hard to better understand these details — and we will update this post when we have more information, or if the facts change. In addition, if we find more affected accounts, we will immediately reset their access tokens,” the executive assured.
He added that “People’s privacy and security is incredibly important, and we’re sorry this happened,” and that users do not need to change their passwords.