Get the Whitepaper called Exploiting Unrestricted File Upload via Plugin Uploader in WordPress.
You can download it from the following link: https://packetstormsecurity.com/files/download/157985/exploiting-uploads.pdf
Source: https://packetstormsecurity.com/files/157985/Exploiting-Unrestricted-File-Upload-Via-Plugin-Uploader-In-WordPress.html