Summary:When using the Facebook ‘Messages’ tab, there is a feature to attach a file. Using this feature normally, the site won’t allow a user to attach an executable file. A bug was discovered to subvert this security mechanisms. Note, you do NOT have to be friends with the user to send them a message with an attachment.
Description:
When attaching an executable file, Facebook will return an error message stating:
“Error Uploading: You cannot attach files of that type.”
When uploading a file attachment to Facebook we captured the web browsers POST request being sent to the web server. Inside this POST request reads the line:
