The access token contains information such as security credentials for a login session, user identity, and the permission. By having the access tokens hackers can take over user accounts without account passwords and without completing two-factor authentication.
Facebook Security Breach Noticed
Facebook noticed the Bug on September 25 and they said the bug was fixed now and reported to law enforcement agencies. Facebook not revealed any technical details of the vulnerability.
The social media giant said “we have reset the access tokens of the almost 50 million accounts and as a 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,” reads Facebook security breach update.
So as the token reset the affected users need to lo back in with the Facebook or any other apps that use Facebook login.
Facebook made changes with code for View as a feature while introducing video uploading feature in July 2017 and the attackers found the vulnerability in the code and use it to get the access tokens.
Temporarily facebook turned off View as a feature, that lets you see how your profile looks for others.
The social media giant said we just started the 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.
Facebook under heavy criticism after Cambridge Analytica scandal which impacts more than 87 Million users and thereafter many Quiz app NameTests spotted exposing more than 120 million users personal data publically in third-party sites.