Facebook has fixed a security bug that could have allowed attackers to delete a user’s photos.
The bug was discovered by Laxman Muthiyah, who was awarded a $12,500 bounty for his finding. According to Facebook’s developer documentation, photo albums cannot be deleted using the album node in Graph API, he wrote in a blog post. After attempting to delete one of his own photo albums using the graph explorer access token, he received an error message that indicated to him that another application may have the ability to make this API call.
He eventually discovered that by using a mobile access token from his Android device, he was able to fool Facebook into deleting the photo album of another person.
Technical details of the proof-of-concept Muthiyah designed can be read here.
“We received a report about an issue with our Graph API and quickly fixed it within two hours of verifying the claims,” according to a Facebook spokesperson. “To be clear, triggering this issue would have required knowledge of the ID of the target photo album, as well as permission to view the album based on the album’s privacy settings. We’d like to thank the researcher who reported the issue to us through our bug bounty program.”
In practice Facebook probably operates rate limiting or other countermeasures that would prevent a single device from using this bug to engage in the mass deletion of photos – and even if it doesn’t, the social network is so large an attacker would probably struggle to delete albums as fast as people on Facebook create new ones, noted Mark Stockley on Sophos’ Naked Security blog.
“But that’s just a question of horsepower, and horsepower is easy on the internet – there are kids running botnets of 60,000 computers,” he wrote.
Muthiyah thanked Facebook for its quick response.