When Facebook debuted a new polling feature earlier this month, it also introduced a vulnerability that could have allowed a malicious actor to delete any photo saved to the social media site.
Darabi found that when a user created a new poll, the feature would send a request containing a gif URL or image ID – but a malicious actor could have changed the field value to any other image's ID, making that image appear there instead. Then, upon deleting the poll, the image would be completely deleted – not just from the poll, but from Facebook itself.
Darabi said he earned a $10,000 bug bounty for his discovery.
“This kind of boo-boo suggests a more serious permissions-based problem with Facebook,” writes security expert Graham Cluley on his personal blog. “You may be able to add any image that you can find on Facebook (‘read access') but there's no way that that should translate into meaning that you can also command Facebook to delete the image (‘write access').