Facebook resets log in tokens of 90 million users after attackers exploited system

Sept 29, 2018 (LBO) – Facebook has discovered a vulnerability that affected almost 50 million accounts after an external actor exploited their systems.

Facebook said it’s 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,” Facebook said.



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. “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 into 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.



Facebook has temporarily turned off the “View As” feature while they conduct a thorough security review. "Since we’ve only just started our investigation, we have yet to determine whether these accounts were misused or any information accessed," Facebook added.



"We also don’t know who’s behind these attacks or where they’re based. We’re working hard to better understand these details.



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