Facebook security has become a hot topic even before Mark Zuckerberg‘s appearance before a congressional committee in Washington
The company says that attackers exploited a vulnerability in Facebook’s code that impacted “View As.” View As is a feature that lets people see what their profile looks like to another user. This vulnerability allowed the attackers to steal Facebook access tokens which they used to take over accounts. Tokens act like digital keys that keep users logged into Facebook’s system so they do not have to continually log in.
Here is the action we have already taken. First, we’ve fixed the vulnerability and informed law enforcement.
Second, we have 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.
Third, we’re 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’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.
Facebook has apologized for the security incident and was quick to assure users they are dealing with it. The company says there is no need for users to change passwords. Users who have trouble logging into Facebook should visit Facebook’s Help Center.
Last Updated on September 28, 2018.