Revolution Slider <= 6.6.12 - Author+ Remote Code Execution

1. Create a new slider. Set its background image to an image on your server.
2. Save the slider, exit the slider edit UI, and go to Slider Revolution > Overview.
3. In the dropdown menu for the Slider you just created, click "Export".
4. Unzip the export.
5. In the `images` directory, exchange the image file with a file `poc.php` with the following contents:

    <?php echo "pwned"; ?>

6. In the `slider_export.txt` file, replace the path to the image file with the path to the `poc.php` file.
7. Note the value of the `alias` attribute. This will be needed later.
8. Zip the `images` directory and `slider_export.txt` file.
9. On the site, go to Slider Revolution > Overview.
10. Click on "Manual Import" and upload your zip file.
11. Note that the `poc.php` file has been uploaded to `/wp-content/uploads/revslider/<alias>/poc.php`.
12. Ensure that your server is configured to allow PHP execution from the `wp-content/uploads` directory, and visit `http://yoursite.com/wp-content/uploads/revslider/<alias>/poc.php` to see the RCE.