Facebook announces security attack affecting 50 million users

Facebook CEO Mark Zuckerberg.Getty

• Facebook announced a major new security breach on Friday.
• 50 million users accounts were affected by the attack, in which attackers were able to take over users’ accounts.
• It’s not yet clear who’s behind the attack.

Facebook just disclosed a major new hack affecting almost 50 million users.

The Silicon Valley tech firm discovered on Tuesday that attackers had taken advantage of a security flaw to take over users’ accounts. The company’s stock dropped 3% on the news.

Facebook’s VP of Product Management Guy Rosen wrote in a blog post announcing the news on Friday: “Our investigation is still in its early stages. 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.

“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.”

Facebook says it’s not yet clear who is behind the attack.

The company is holding a press call on Friday morning with the media; Business Insider will attend and update this story with more information as it becomes available. 

This story is developing… 

Visit Markets Insider for constantly updated market quotes for individual stocks, ETFs, indices, commodities and currencies traded around the world. Go Now!