29 September 2018

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Know How Hackers Hacked 50 Million Facebook User Accounts

Know How Hackers Hacked 50 Million Facebook User Accounts

In a blog post Facebook wrote following, On the afternoon of Tuesday, September 25, our engineering team discovered a security issue affecting almost 50 million accounts.
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.

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.

Facebook also said that they have fixed the vulnerability and informed law enforcement.

Facebook temporarily turned off the View As feature

Now let us understand How the Hackers successfully hacked the 50 million accounts of Facebook users.

Hackers attacked Facebook systems and exploited a vulnerability that exposed Facebook access tokens for people’s accounts in HTML when we rendered a particular component of the “View As” feature. The vulnerability was the result of the interaction of three distinct bugs:

First: View As is a privacy feature that lets people see what their own profile looks like to someone else. View As should be a view-only interface. However, for one type of composer (the box that lets you post content to Facebook) — specifically the version that enables people to wish their friends happy birthday — View As incorrectly provided the opportunity to post a video.

Second: A new version of our video uploader (the interface that would be presented as a result of the first bug), introduced in July 2017, incorrectly generated an access token that had the permissions of the Facebook mobile app.

Third: When the video uploader appeared as part of View As, it generated the access token not for you as the viewer, but for the user that you were looking up.
It was the combination of these three bugs that became a vulnerability: when using the View As feature to view your profile as a friend, the code did not remove the composer that lets people wish you happy birthday; the video uploader would generate an access token when it shouldn’t have; and when the access token was generated, it was not for you but the person being looked up. That access token was then available in the HTML of the page, which the attackers were able to extract and exploit to log in as another user.

The attackers were then able to pivot from that access token to other accounts, performing the same actions and obtaining further access tokens.
“It was the combination of those three bugs that became a vulnerability. Now, this was discovered by attackers,” “Those attackers, in order to run the attack, needed not just to find this vulnerability, but they needed to get an access token and then to pivot that access token to other accounts and then look up other users in order to get further access tokens.”

 “This is a complex interaction of multiple bugs that happened together,”

 Now what will happen with the stolen data? I think following things will happen with the stolen Facebook data?

1-data will get sold to companies, even political parties will buy that data.

2- In past we saw that how using FB data one can change the mind of a voter and get the votes and win elections.

3-Blackmail may happen if you have uploaded sensitive information in FB.

4- Your other accounts may get hacked if you have put information regarding them on FB. If your account was impacted it means that a hacker could have accessed any account that you log into using Facebook.

Reality views by sm -

Saturday, September 29, 2018

Tags – Facebook Hack Hacker 50 Million