Facebook (FB) today announced that some 50 million user accounts were impacted by a security breach that allowed the attackers to potentially take over users’ profiles.
“This is a serious issue, and we’ve already taken a number of steps to address this,” CEO Mark Zuckerberg explained during a press call.
“We’re in touch with law enforcement to help identify the attackers,” Zuckerberg added.
In a press release Facebook’s VP of product management Guy Rosen explained that the issue was the result of an exploit found in the social media site’s View As feature, which lets users see what their own profiles would look like from the perspective of other users.
“Our investigation is still in its early stages,” Rosen explained via a blog post. “But 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,” Rosen continued. “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.”
According to Rosen, Facebook has already fixed the flaw and reset the access tokens for the 50 million impacted accounts. The company has also reset the access tokens to an additional 40 million accounts that were the subject of a View As look up as a precautionary measure. In total, 90 million users will have to log back into their Facebook accounts the next time they open the Facebook app or use an app that uses a Facebook login.
In his post, Rosen said that Facebook still isn’t sure who the attackers were that used the exploit, or if any information was accessed.
Facebook has faced increased scrutiny since the Cambridge Analytica scandal broke in April, and the issue of user privacy and data protection has become a matter of national importance. On Wednesday the Senate Commerce Committee held a public hearing on user privacy and data protection, which included representatives from Apple, Amazon, AT&T, Google, Twitter and Charter.
Facebook’s Sheryl Sandberg also attended a meeting in front of the Senate Intelligence Committee last month discussing how the company was working to prevent future election interference similar to what happened during the 2016 election.
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