WordPress Plugin Site Editor 1.1.1 - Local File Inclusion

Product: Site Editor Wordpress Plugin - https://wordpress.org/plugins/site-editor/
Vendor: Site Editor
Tested version: 1.1.1
CVE ID: CVE-2018-7422

** CVE description **
A Local File Inclusion vulnerability in the Site Editor plugin through 1.1.1 for WordPress allows remote attackers to retrieve arbitrary files via the ajax_path parameter to editor/extensions/pagebuilder/includes/ajax_shortcode_pattern.php.

** Technical details **
In site-editor/editor/extensions/pagebuilder/includes/ajax_shortcode_pattern.php:5, the value of the ajax_path parameter is used for including a file with PHP’s require_once(). This parameter can be controlled by an attacker and is not properly sanitized.

Vulnerable code:
if( isset( $_REQUEST['ajax_path'] ) && is_file( $_REQUEST['ajax_path'] ) && file_exists( $_REQUEST['ajax_path'] ) ){
    require_once $_REQUEST['ajax_path'];
}

https://plugins.trac.wordpress.org/browser/site-editor/trunk/editor/extensions/pagebuilder/includes/ajax_shortcode_pattern.php?rev=1640500#L5

By providing a specially crafted path to the vulnerable parameter, a remote attacker can retrieve the contents of sensitive files on the local system.

** Proof of Concept **
http://<host>/wp-content/plugins/site-editor/editor/extensions/pagebuilder/includes/ajax_shortcode_pattern.php?ajax_path=/etc/passwd

** Solution **
No fix available yet.

** Timeline **
03/01/2018: author contacted through siteeditor.org's contact form; no reply
16/01/2018: issue report filled on the public GitHub page with no technical details
18/01/2018: author replies and said he replied to our e-mail 8 days ago (could not find the aforementioned e-mail at all); author sends us "another" e-mail
19/01/2018: report sent; author says he will fix this issue "very soon"
31/01/2018: vendor contacted to ask about an approximate release date and if he needs us to postpone the disclosure; no reply
14/02/2018: WP Plugins team contacted; no reply
06/03/2018: vendor contacted; no reply
07/03/2018: vendor contacted; no reply
15/03/2018: public disclosure

** Credits **
Vulnerability discovered by Nicolas Buzy-Debat working at Orange Cyberdefense Singapore (CERT-LEXSI).

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Best Regards,

Nicolas Buzy-Debat
Orange Cyberdefense Singapore (CERT-LEXSI)