Class: Msf::Payload

Inherits:
Module show all
Defined in:
lib/msf/core/payload.rb

Overview

This class represents the base class for a logical payload. The framework automatically generates payload combinations at runtime which are all extended for this Payload as a base class.

Defined Under Namespace

Modules: Aix, Android, Bsd, Firefox, Generic, Hardware, JSP, Java, Linux, Mainframe, Multi, Netware, NodeJS, Osx, Php, Pingback, Python, R, Ruby, Single, Solaris, Stager, TransportConfig, Type, Windows Classes: Apk, MachO, UUID

Constant Summary

Constants inherited from Module

Module::REPLICANT_EXTENSION_DS_KEY

Constants included from Module::ModuleInfo

Module::ModuleInfo::UpdateableOptions

Instance Attribute Summary collapse

Attributes inherited from Module

#error, #job_id, #license, #platform, #privileged, #references, #user_data

Attributes included from Framework::Offspring

#framework

Attributes included from Module::UUID

#uuid

Attributes included from Rex::Ui::Subscriber::Input

#user_input

Attributes included from Rex::Ui::Subscriber::Output

#user_output

Attributes included from Module::Privileged

#priveli, #privileged

Attributes included from Module::Options

#options

Attributes included from Module::ModuleStore

#module_store

Attributes included from Module::ModuleInfo

#module_info

Attributes included from Module::FullName

#aliased_as

Attributes included from Module::DataStore

#datastore

Attributes included from Module::Author

#author

Attributes included from Module::Arch

#arch

Attributes included from Module::Alert

#alerts, #you_have_been_warned

Class Method Summary collapse

Instance Method Summary collapse

Methods inherited from Module

#black_listed_auth_filenames, cached?, #debugging?, #default_cred?, #fail_with, #file_path, #framework, #has_check?, #orig_cls, #owner, #perform_extensions, #platform?, #platform_to_s, #post_auth?, #register_extensions, #register_parent, #replicant, #required_cred_options, #set_defaults, #workspace

Methods included from Module::Reliability

#reliability, #reliability_to_s

Methods included from Module::Stability

#stability, #stability_to_s

Methods included from Module::SideEffects

#side_effects, #side_effects_to_s

Methods included from Module::UUID

#generate_uuid

Methods included from Module::UI

#init_ui

Methods included from Module::UI::Message

#print_error, #print_good, #print_prefix, #print_status, #print_warning

Methods included from Module::UI::Message::Verbose

#vprint_error, #vprint_good, #vprint_status, #vprint_warning

Methods included from Module::UI::Line

#print_line, #print_line_prefix

Methods included from Module::UI::Line::Verbose

#vprint_line

Methods included from Rex::Ui::Subscriber

#copy_ui, #init_ui, #reset_ui

Methods included from Rex::Ui::Subscriber::Input

#gets

Methods included from Rex::Ui::Subscriber::Output

#flush, #print, #print_blank_line, #print_error, #print_good, #print_line, #print_status, #print_warning

Methods included from Module::Type

#auxiliary?, #encoder?, #evasion?, #exploit?, #nop?, #payload?, #post?

Methods included from Module::Ranking

#rank, #rank_to_h, #rank_to_s

Methods included from Module::Privileged

#privileged?

Methods included from Module::Options

#deregister_options, #register_advanced_options, #register_evasion_options, #register_options, #validate

Methods included from Module::Network

#comm, #support_ipv6?, #target_host, #target_port

Methods included from Module::ModuleStore

#[], #[]=

Methods included from Module::ModuleInfo

#alias, #description, #disclosure_date, #info_fixups, #merge_check_key, #merge_info, #merge_info_advanced_options, #merge_info_alias, #merge_info_description, #merge_info_evasion_options, #merge_info_name, #merge_info_options, #merge_info_string, #merge_info_version, #name, #notes, #update_info

Methods included from Module::FullName

#aliases, #fullname, #promptname, #realname, #refname, #shortname

Methods included from Module::DataStore

#import_defaults, #import_target_defaults, #share_datastore

Methods included from Module::Compatibility

#compat, #compatible?, #init_compat

Methods included from Module::Author

#author_to_s, #each_author

Methods included from Module::Auth

#store_valid_credential

Methods included from Module::Arch

#arch?, #arch_to_s, #each_arch

Methods included from Module::Alert

#add_alert, #add_error, #add_warning, #alert_user, #errors, #get_alerts, included, #is_usable?, #warnings

Constructor Details

#initialize(info = {}) ⇒ Payload

Creates an instance of a payload module using the supplied information.


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# File 'lib/msf/core/payload.rb', line 51

def initialize(info = {})
  super
  self.can_cleanup = true

  #
  # Gets the Dependencies if the payload requires external help
  # to work
  #
  self.module_info['Dependencies'] = self.module_info['Dependencies'] || []

  # If this is a staged payload but there is no stage information,
  # then this is actually a stager + single combination.  Set up the
  # information hash accordingly.
  if self.class.include?(Msf::Payload::Single) and
    self.class.include?(Msf::Payload::Stager)
    self.module_info['Stage'] = {}

    if self.module_info['Payload']
      self.module_info['Stage']['Payload']  = self.module_info['Payload']['Payload'] || ""
      self.module_info['Stage']['Assembly'] = self.module_info['Payload']['Assembly'] || ""
      self.module_info['Stage']['Offsets']  = self.module_info['Payload']['Offsets'] || {}
    else
      self.module_info['Stage']['Payload']  = ""
      self.module_info['Stage']['Assembly'] = ""
      self.module_info['Stage']['Offsets']  = {}
    end

    @staged = true
  else
    @staged = false
  end

  # Update the module info hash with the connection type
  # that is derived from the handler for this payload.  This is
  # used for compatibility filtering purposes.
  self.module_info['ConnectionType'] = connection_type
end

Instance Attribute Details

#appendObject

This attribute holds the string that should be appended to the buffer when it's generated.


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# File 'lib/msf/core/payload.rb', line 529

def append
  @append
end

#assoc_exploitObject

If this payload is associated with an exploit, the assoc_exploit attribute will point to that exploit instance.


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# File 'lib/msf/core/payload.rb', line 540

def assoc_exploit
  @assoc_exploit
end

#available_spaceObject

The amount of space available to the payload, which may be nil, indicating that the smallest possible payload should be used.


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# File 'lib/msf/core/payload.rb', line 546

def available_space
  @available_space
end

#can_cleanupObject

This attribute designates if the payload supports onsession() method calls (typically to clean up artifacts)


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# File 'lib/msf/core/payload.rb', line 519

def can_cleanup
  @can_cleanup
end

#prependObject

This attribute holds the string that should be prepended to the buffer when it's generated.


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# File 'lib/msf/core/payload.rb', line 524

def prepend
  @prepend
end

#prepend_encoderObject

This attribute holds the string that should be prepended to the encoded version of the payload (in front of the encoder as well).


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# File 'lib/msf/core/payload.rb', line 534

def prepend_encoder
  @prepend_encoder
end

Class Method Details

.cached_sizeObject

This method returns an optional cached size value


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# File 'lib/msf/core/payload.rb', line 159

def self.cached_size
  csize = (const_defined?('CachedSize')) ? const_get('CachedSize') : nil
  csize == :dynamic ? nil : csize
end

.dynamic_size?Boolean

This method returns whether the payload generates variable-sized output

Returns:

  • (Boolean)

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# File 'lib/msf/core/payload.rb', line 167

def self.dynamic_size?
  csize = (const_defined?('CachedSize')) ? const_get('CachedSize') : nil
  csize == :dynamic
end

.typeObject

Returns MODULE_PAYLOAD to indicate that this is a payload module.


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# File 'lib/msf/core/payload.rb', line 98

def self.type
  return Msf::MODULE_PAYLOAD
end

Instance Method Details

#apply_prepends(raw) ⇒ Object

A placeholder stub, to be overriden by mixins


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# File 'lib/msf/core/payload.rb', line 468

def apply_prepends(raw)
  raw
end

#assemblyObject

Returns the assembly string that describes the payload if one exists.


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# File 'lib/msf/core/payload.rb', line 212

def assembly
  return module_info['Payload'] ? module_info['Payload']['Assembly'] : nil
end

#assembly=(asm) ⇒ Object

Sets the assembly string that describes the payload If this method is used to define the payload, a payload with no offsets will be created


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# File 'lib/msf/core/payload.rb', line 220

def assembly=(asm)
  module_info['Payload'] ||= {'Offsets' => {} }
  module_info['Payload']['Assembly'] = asm
end

#badcharsObject

Returns the string of bad characters for this payload, if any.


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# File 'lib/msf/core/payload.rb', line 112

def badchars
  return self.module_info['BadChars']
end

#build(asm, off = {}) ⇒ String (protected)

If the payload has assembly that needs to be compiled, do so now.

Blobs will be cached in the framework's PayloadSet

Parameters:

  • asm (String)

    Assembly code to be assembled into a raw payload

Returns:

  • (String)

    The final, assembled payload

Raises:

  • ArgumentError if asm is blank

See Also:


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# File 'lib/msf/core/payload.rb', line 559

def build(asm, off={})
  if(asm.nil? or asm.empty?)
    raise ArgumentError, "Assembly must not be empty"
  end

  # Use the refname so blobs can be flushed when the module gets
  # reloaded and use the hash value to ensure that we're actually
  # getting the right blob for the given assembly.
  cache_key   = refname + asm.hash.to_s
  cache_entry = framework.payloads.check_blob_cache(cache_key)

  off.each_pair { |option, val|
    if (val[1] == 'RAW')
      asm = asm.gsub(/#{option}/){ datastore[option] }
      off.delete(option)
    end
  }

  # If there is a valid cache entry, then we don't need to worry about
  # rebuilding the assembly
  if cache_entry
    # Update the local offsets from the cache
    off.each_key { |option|
      off[option] = cache_entry[1][option]
    }

    # Return the cached payload blob
    return cache_entry[0].dup
  end

  # Assemble the payload from the assembly
  a = self.arch
  if a.kind_of? Array
    a = self.arch.first
  end
  cpu = case a
    when ARCH_X86    then Metasm::Ia32.new
    when ARCH_X64    then Metasm::X86_64.new
    when ARCH_PPC    then Metasm::PowerPC.new
    when ARCH_ARMLE  then Metasm::ARM.new
    when ARCH_MIPSLE then Metasm::MIPS.new(:little)
    when ARCH_MIPSBE then Metasm::MIPS.new(:big)
    else
      elog("Broken payload #{refname} has arch unsupported with assembly: #{module_info["Arch"].inspect}")
      elog("Call stack:\n#{caller.join("\n")}")
      return ""
    end
  sc = Metasm::Shellcode.assemble(cpu, asm).encoded

  # Calculate the actual offsets now that it's been built
  off.each_pair { |option, val|
    off[option] = [ sc.offset_of_reloc(option) || val[0], val[1] ]
  }

  # Cache the payload blob
  framework.payloads.add_blob_cache(cache_key, sc.data, off)

  # Return a duplicated copy of the assembled payload
  sc.data.dup
end

#cached_sizeObject

This method returns an optional cached size value


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# File 'lib/msf/core/payload.rb', line 175

def cached_size
    self.class.cached_size
end

#compatible_encodersObject

Returns the array of compatible encoders for this payload instance.


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# File 'lib/msf/core/payload.rb', line 440

def compatible_encoders
  encoders = []

  framework.encoders.each_module_ranked(
    'Arch' => self.arch, 'Platform' => self.platform) { |name, mod|
    encoders << [ name, mod ]
  }

  return encoders
end

#compatible_nopsObject

Returns the array of compatible nops for this payload instance.


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# File 'lib/msf/core/payload.rb', line 454

def compatible_nops
  nops = []

  framework.nops.each_module_ranked(
    'Arch' => self.arch) { |name, mod|
    nops << [ name, mod ]
  }

  return nops
end

#connection_typeObject

Returns the module's connection type, such as reverse, bind, noconn, or whatever else the case may be.


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# File 'lib/msf/core/payload.rb', line 253

def connection_type
  handler_klass.general_handler_type
end

#conventionObject

Returns the staging convention that the payload uses, if any. This is used to make sure that only compatible stagers and stages are built (where assumptions are made about register/environment initialization state and hand-off).


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# File 'lib/msf/core/payload.rb', line 245

def convention
  module_info['Convention']
end

#dependenciesObject

Returns the compiler dependencies if the payload has one


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# File 'lib/msf/core/payload.rb', line 235

def dependencies
  module_info['Dependencies']
end

#dynamic_size?Boolean

This method returns whether the payload generates variable-sized output

Returns:

  • (Boolean)

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# File 'lib/msf/core/payload.rb', line 182

def dynamic_size?
    self.class.dynamic_size?
end

#generateObject

Generates the payload and returns the raw buffer to the caller.


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# File 'lib/msf/core/payload.rb', line 290

def generate
  internal_generate
end

#generate_completeObject

Generates the payload and returns the raw buffer to the caller, handling any post-processing tasks, such as prepended code stubs.


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# File 'lib/msf/core/payload.rb', line 297

def generate_complete
  apply_prepends(generate)
end

#handler_klassObject

Return the connection associated with this payload, or none if there isn't one.


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# File 'lib/msf/core/payload.rb', line 269

def handler_klass
  return module_info['Handler'] || Msf::Handler::None
end

#internal_generateObject (protected)

Generate the payload using our local payload blob and offsets


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# File 'lib/msf/core/payload.rb', line 623

def internal_generate
  # Build the payload, either by using the raw payload blob defined in the
  # module or by actually assembling it
  if assembly and !assembly.empty?
    raw = build(assembly, offsets)
  else
    raw = payload.dup
  end

  # If the payload is generated and there are offsets to substitute,
  # do that now.
  if (raw and offsets)
    substitute_vars(raw, offsets)
  end

  return raw
end

#merge_name(info, val) ⇒ Object (protected)

Merge the name to prefix the existing one and separate them with a comma


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# File 'lib/msf/core/payload.rb', line 651

def merge_name(info, val)
  if (info['Name'])
    info['Name'] = val + ',' + info['Name']
  else
    info['Name'] = val
  end
end

#offsetsObject

Returns the offsets to variables that must be substitute, if any.


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# File 'lib/msf/core/payload.rb', line 228

def offsets
  return module_info['Payload'] ? module_info['Payload']['Offsets'] : nil
end

#on_session(session) ⇒ Object

Once an exploit completes and a session has been created on behalf of the payload, the framework will call the payload's on_session notification routine to allow it to manipulate the session prior to handing off control to the user.


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# File 'lib/msf/core/payload.rb', line 484

def on_session(session)

  # If this payload is associated with an exploit, inform the exploit
  # that a session has been created and potentially shut down any
  # open sockets. This allows active exploits to continue hammering
  # on a service until a session is created.
  if (assoc_exploit)

    # Signal that a new session is created by calling the exploit's
    # on_new_session handler. The default behavior is to set an
    # instance variable, which the exploit will have to check.
    begin
      assoc_exploit.on_new_session(session)
    rescue ::Exception => e
      dlog("#{assoc_exploit.refname}: on_new_session handler triggered exception: #{e.class} #{e} #{e.backtrace}", 'core', LEV_1)	rescue nil
    end

    # Set the abort sockets flag only if the exploit is not passive
    # and the connection type is not 'find'
    if (
      (assoc_exploit.exploit_type == Exploit::Type::Remote) and
      (assoc_exploit.passive? == false) and
      (connection_type != 'find')
       )
       assoc_exploit.abort_sockets
    end

  end

end

#payloadObject

Returns the raw payload that has not had variable substitution occur.


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# File 'lib/msf/core/payload.rb', line 205

def payload
  return module_info['Payload'] ? module_info['Payload']['Payload'] : nil
end

#payload_typeObject

Returns the type of payload, either single or staged. Stage is the default because singles and stagers are encouraged to include the Single and Stager mixin which override the payload_type.


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# File 'lib/msf/core/payload.rb', line 129

def payload_type
  return Type::Stage
end

#payload_type_sObject

Returns the string version of the payload type


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# File 'lib/msf/core/payload.rb', line 136

def payload_type_s
  case payload_type
    when Type::Stage
      return "stage"
    when Type::Stager
      return "stager"
    when Type::Single
      return "single"
    else
      return "unknown"
  end
end

#raw_to_db(raw) ⇒ Object

Convert raw bytes to metasm-ready 'db' encoding format eg. “x90xCC” => “db 0x90,0xCC”

Parameters:

  • raw (Array)

    Byte array to encode.


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# File 'lib/msf/core/payload.rb', line 307

def raw_to_db(raw)
  raw.unpack("C*").map {|c| "0x%.2x" % c}.join(",")
end

#replace_var(raw, name, offset, pack) ⇒ Object

Replaces an individual variable in the supplied buffer at an offset using the given pack type. This is here to allow derived payloads the opportunity to replace advanced variables.


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# File 'lib/msf/core/payload.rb', line 426

def replace_var(raw, name, offset, pack)
  return false
end

#save_registersObject

The list of registers that should be saved by any NOP generators or encoders, if possible.


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# File 'lib/msf/core/payload.rb', line 120

def save_registers
  return self.module_info['SaveRegisters']
end

#sessionObject

Returns the session class that is associated with this payload and will be used to create a session as necessary.


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# File 'lib/msf/core/payload.rb', line 277

def session
  return module_info['Session']
end

#sizeObject

Returns the payload's size. If the payload is staged, the size of the first stage is returned.


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# File 'lib/msf/core/payload.rb', line 190

def size
  pl = nil
  begin
    pl = generate()
  rescue Metasploit::Framework::Compiler::Mingw::UncompilablePayloadError
  rescue NoCompatiblePayloadError
  rescue PayloadItemSizeError
  end
  pl ||= ''
  pl.length
end

#staged?Boolean

This method returns whether or not this payload uses staging.

Returns:

  • (Boolean)

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# File 'lib/msf/core/payload.rb', line 152

def staged?
  (@staged or payload_type == Type::Stager or payload_type == Type::Stage)
end

#substitute_vars(raw, offsets) ⇒ Object

Substitutes variables with values from the module's datastore in the supplied raw buffer for a given set of named offsets. For instance, RHOST is substituted with the RHOST value from the datastore which will have been populated by the framework.

Supported packing types:

  • ADDR (foo.com, 1.2.3.4)

  • ADDR6 (foo.com, fe80::1234:5678:8910:1234)

  • ADDR16MSB, ADD16LSB, ADDR22MSB, ADD22LSB (foo.com, 1.2.3.4) Advanced packing types for 16/16 and 22/10 bits substitution. The 16 bits types uses two offsets indicating where the 16 bits pair will be substituted, while the 22 bits types uses two offsets indicating the instructions where the 22/10 bits pair will be substituted. Normally these are offsets to “sethi” and “or” instructions on SPARC architecture.

  • HEX (0x12345678, “x41x42x43x44”)

  • RAW (raw bytes)


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# File 'lib/msf/core/payload.rb', line 330

def substitute_vars(raw, offsets)
  offsets.each_pair { |name, info|
    offset, pack = info

    # Give the derived class a chance to substitute this variable
    next if (replace_var(raw, name, offset, pack) == true)

    # Now it's our turn...
    if ((val = datastore[name]))
      if (pack == 'ADDR')
        val = Rex::Socket.resolv_nbo(val)

        # Someone gave us a funky address (ipv6?)
        if(val.length == 16)
          raise RuntimeError, "IPv6 address specified for IPv4 payload."
        end
      elsif (pack == 'ADDR6')
        val = Rex::Socket.resolv_nbo(val)

        # Convert v4 to the v6ish address
        if(val.length == 4)
          nip = "fe80::5efe:" + val.unpack("C*").join(".")
          val = Rex::Socket.resolv_nbo(nip)
        end
      elsif (['ADDR16MSB', 'ADDR16LSB', 'ADDR22MSB', 'ADDR22LSB'].include?(pack))
        val = Rex::Socket.resolv_nbo(val)

        # Someone gave us a funky address (ipv6?)
        if(val.length == 16)
          raise RuntimeError, "IPv6 address specified for IPv4 payload."
        end
      elsif (pack == 'RAW')
        # Just use the raw value...
      else
        # Check to see if the value is a hex string.  If so, convert
        # it.
        if val.kind_of?(String)
          if val =~ /^\\x/n
            val = [ val.gsub(/\\x/n, '') ].pack("H*").unpack(pack)[0]
          elsif val =~ /^0x/n
            val = val.hex
          end
        end

        # NOTE:
        # Packing assumes integer format at this point, should fix...
        val = [ val.to_i ].pack(pack)
      end

      # Substitute it
      if (['ADDR16MSB', 'ADDR16LSB'].include?(pack))
        if (offset.length != 2)
          raise RuntimeError, "Missing value for payload offset, there must be two offsets."
        end

        if (pack == 'ADDR16LSB')
          val = val.unpack('N').pack('V')
        end

        raw[offset[0], 2] = val[0, 2]
        raw[offset[1], 2] = val[2, 2]

      elsif (['ADDR22MSB', 'ADDR22LSB'].include?(pack))
        if (offset.length != 2)
          raise RuntimeError, "Missing value for payload offset, there must be two offsets."
        end

        if (pack == 'ADDR22LSB')
          val = val.unpack('N').pack('V')
        end

        hi = (0xfffffc00 & val) >> 10
        lo = 0x3ff & val

        ins = raw[offset[0], 4]
        raw[offset[0], 4] = ins | hi

        ins = raw[offset[1], 4]
        raw[offset[1], 4] = ins | lo

      else
        raw[offset, val.length] = val

      end
    else
      wlog("Missing value for payload offset #{name}, skipping.",
        'core', LEV_3)
    end
  }
end

#symbol_lookupObject

Returns the method used by the payload to resolve symbols for the purpose of calling functions, such as ws2ord.


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# File 'lib/msf/core/payload.rb', line 261

def symbol_lookup
  module_info['SymbolLookup']
end

#typeObject

Returns MODULE_PAYLOAD to indicate that this is a payload module.


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# File 'lib/msf/core/payload.rb', line 105

def type
  return Msf::MODULE_PAYLOAD
end