Mr. Guy Rosen, the Vice President, Product Management of Facebook, says 50 million Facebook accounts were affected by security issue.
Rosen, in a statement on Friday, said that in the afternoon of Tuesday, September 25, Facebook’s engineering team discovered a security issue affecting almost 50 million accounts.
He said that the company was taking the issue seriously and wanted to let everyone know what happened, and the immediate action taken to protect people’s security.
According to him, investigation was still in its early stages.
“But it is clear that 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,” he said.
The Vice President said that Facebook had already fixed the vulnerability and informed law enforcement.
He said that the company had reset the access tokens of the almost 50 million accounts in order to protect their security.
Rosen said that Facebook had also taken precautionary step of resetting access tokens for another 40 million accounts that had been subject to a “View As” look-up in the last year.
He said that as a result, around 90 million people would now have to log back into Facebook, or any of their apps that use Facebook Login.
According to him, after they have logged back in, people will get a notification at the top of their News Feed explaining what happened.
“We are temporarily turning off the “View As” feature, while we conduct a thorough security review.
“This 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 have only just started our investigation, we have yet to determine whether these accounts were misused or any information accessed,” he said.