How to hack Facebook accounts exploiting CSRF in Oculus app

Facebook has fixed a couple of vulnerabilities that could have been exploited by attackers to hijack accounts by abusing integration with the Oculus virtual reality headset.

In March 2014, Facebook founder Mark Zuckerberg announced the acquisition of Oculus VR and included the handsets produced by the company to its bug bounty program.

White hat hackers discovered several vulnerabilities in Oculus platform since, including the ones addressed now by Facebook.

The flaws were reported in October by the security consultant Josip Franjković who analyzed the Oculus application for Windows.

“Oculus enables users to connect their Facebook accounts for a more “social” experience. This can be done using both the native Windows Oculus application and using browsers.” wrote Franjković. “I took a deeper look at the native Windows flow, and found a CSRF vulnerability which allowed me to connect a victim’s Facebook account to attacker’s Oculus account. Once connected, the attacker could extract the victim’s access token, and use Facebook’s GraphQL queries to take over the account.”

Facebook oculus

One of the features implemented by the Oculus application is the authentication to a Facebook account, Franjkovic discovered that attackers could have exploited specially crafted GraphQL queries to connect any user’s Facebook account to their Oculus account.

GraphQL is a query language created by Facebook in 2012 for describing the capabilities and requirements of data models for client‐server applications, a GraphQL query is a string that is sent to a server to be interpreted and fulfilled, which then returns JSON back to the client.

Franjkovic discovered that a specially crafted query allowed an attacker to obtain the victim’s access token and use it to impersonate the victim by accessing his account.

In a proof of concept attack, Franjkovic shows how to use a specially crafted query to add a new mobile phone number to the targeted account and use it to reset the victim’s password.

The vulnerability was reported to Facebook on October 24, the social network giant temporary solved the issue by disabling the facebook_login_sso endpoint.

On October 30, Facebook rolled out a patch to address definitively the problem, but a few weeks later, the expert discovered a login cross-site request forgery (CSRF) flaw that could have been exploited to bypass Facebook’s patch.

The experts informed Facebook on November 18 that disabled again the facebook_login_sso endpoint to mitigate the problem. A complete patch was rolled out after a few weeks.

Facebook paid the expert for his discoveries and classified the vulnerabilities as critical.

Step by step procedure exploited by the researcher is described on its blog, below the timeline of the hack:

  • 24th of October, 2017, 03:20 – Report sent to Facebook
  • 24th of October, 2017, 10:50 – First reply from Facebook
  • 24th of October, 2017, 11:30 – Temporary fix for the bug (disabled /facebook_login_sso/ endpoint)
  • 30th of October, 2017 – Bug is now fixed.


Pierluigi Paganini

(Security Affairs –Facebook Oculus, hacking)



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