The bug was identified by a Polish security researcher, who goes by name Lasq. He noticed the vulnerability was abused in wild and he saw the malicious link appeared in a lot of friends Facebook wall.
The link appears to be hosted in AWS bucket and pointed to a comics site, when the user clicked on the link it asks to verify the age and directs to a comics site. In the meantime the link found to be appeared on the user’s Facebook wall.
But with mobile phones the X-Frame-Option was totally ignored, with the Android Facebook App, the vulnerability resides with the mobile version of the Facebook app.
Researcher dug deep and tracked the real issue that “if you are connected from a mobile device, Facebook doesn’t even set an X-Frame-Options header for this site. So this is indeed a feature.”
He reported the issue to the Facebook but they declined the bug saying it is working as intended and the case has been closed within 12 hours from an initial report.
The Researcher said “this “feature” can be extremely easily abused by an attacker to trick Facebook users to unwillingly share something on their wall.” poC can be found here.