Class: Msf::EncodedPayload
- Inherits:
-
Object
- Object
- Msf::EncodedPayload
- Includes:
- Framework::Offspring
- Defined in:
- lib/msf/core/encoded_payload.rb
Overview
This class wrappers an encoded payload buffer and the means used to create one.
Instance Attribute Summary collapse
-
#encoded ⇒ Object
The encoded version of the raw payload plus the NOP sled if one was generated.
-
#encoder ⇒ Object
The encoder that was used.
-
#iterations ⇒ Object
The number of encoding iterations used.
-
#nop ⇒ Object
The NOP generator that was used.
-
#nop_sled ⇒ Object
The NOP sled itself.
-
#nop_sled_size ⇒ Object
The size of the NOP sled.
-
#payload ⇒ Object
writeonly
protected
:nodoc:.
-
#pinst ⇒ Object
protected
The payload instance used to generate the payload.
-
#raw ⇒ Object
The raw version of the payload.
-
#reqs ⇒ Object
protected
The requirements used for generation.
-
#space ⇒ Object
The maximum number of bytes acceptable for the encoded payload.
Attributes included from Framework::Offspring
Class Method Summary collapse
-
.create(pinst, reqs = {}) ⇒ Object
This method creates an encoded payload instance and returns it to the caller.
Instance Method Summary collapse
-
#arch ⇒ Object
An array containing the architecture(s) that this payload was made to run on.
- #compatible_encoders ⇒ Object protected
-
#encode ⇒ Object
Scans for a compatible encoder using ranked precedence and populates the encoded attribute.
-
#encoded_exe(opts = {}) ⇒ Object
Convert the payload to an executable appropriate for its arch and platform.
-
#encoded_jar(opts = {}) ⇒ Object
Generate a jar file containing the encoded payload.
-
#encoded_war(opts = {}) ⇒ Object
Similar to
encoded_jar
but builds a web archive for use in servlet containers such as Tomcat. -
#generate(raw = nil) ⇒ String
This method generates the full encoded payload and returns the encoded payload buffer.
-
#generate_raw ⇒ String
Generates the raw payload from the payload instance.
-
#generate_sled ⇒ Object
Construct a NOP sled if necessary.
- #has_chars?(chars) ⇒ Boolean protected
-
#initialize(framework, pinst, reqs) ⇒ EncodedPayload
constructor
Creates an instance of an EncodedPayload.
- #needs_encoding ⇒ Object protected
-
#platform ⇒ Object
An array containing the platform(s) that this payload was made to run on.
Constructor Details
#initialize(framework, pinst, reqs) ⇒ EncodedPayload
Creates an instance of an EncodedPayload.
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# File 'lib/msf/core/encoded_payload.rb', line 32 def initialize(framework, pinst, reqs) self.framework = framework self.pinst = pinst self.reqs = reqs self.space = reqs['Space'] end |
Instance Attribute Details
#encoded ⇒ Object
The encoded version of the raw payload plus the NOP sled if one was generated.
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# File 'lib/msf/core/encoded_payload.rb', line 494 def encoded @encoded end |
#encoder ⇒ Object
The encoder that was used
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# File 'lib/msf/core/encoded_payload.rb', line 506 def encoder @encoder end |
#iterations ⇒ Object
The number of encoding iterations used
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# File 'lib/msf/core/encoded_payload.rb', line 514 def iterations @iterations end |
#nop ⇒ Object
The NOP generator that was used
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# File 'lib/msf/core/encoded_payload.rb', line 510 def nop @nop end |
#nop_sled ⇒ Object
The NOP sled itself
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# File 'lib/msf/core/encoded_payload.rb', line 502 def nop_sled @nop_sled end |
#nop_sled_size ⇒ Object
The size of the NOP sled
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# File 'lib/msf/core/encoded_payload.rb', line 498 def nop_sled_size @nop_sled_size end |
#payload=(value) ⇒ Object (writeonly, protected)
:nodoc:
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# File 'lib/msf/core/encoded_payload.rb', line 525 def payload=(value) @payload = value end |
#pinst ⇒ Object (protected)
The payload instance used to generate the payload
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# File 'lib/msf/core/encoded_payload.rb', line 534 def pinst @pinst end |
#raw ⇒ Object
The raw version of the payload
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# File 'lib/msf/core/encoded_payload.rb', line 489 def raw @raw end |
#reqs ⇒ Object (protected)
The requirements used for generation
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# File 'lib/msf/core/encoded_payload.rb', line 538 def reqs @reqs end |
#space ⇒ Object
The maximum number of bytes acceptable for the encoded payload
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# File 'lib/msf/core/encoded_payload.rb', line 518 def space @space end |
Class Method Details
.create(pinst, reqs = {}) ⇒ Object
This method creates an encoded payload instance and returns it to the caller.
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# File 'lib/msf/core/encoded_payload.rb', line 20 def self.create(pinst, reqs = {}) # Create the encoded payload instance p = EncodedPayload.new(pinst.framework, pinst, reqs) p.generate(reqs['Raw']) return p end |
Instance Method Details
#arch ⇒ Object
An array containing the architecture(s) that this payload was made to run on
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# File 'lib/msf/core/encoded_payload.rb', line 471 def arch if pinst pinst.arch end end |
#compatible_encoders ⇒ Object (protected)
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# File 'lib/msf/core/encoded_payload.rb', line 562 def compatible_encoders arch = reqs['Arch'] || pinst.arch platform = reqs['Platform'] || pinst.platform encoders = [] framework.encoders.each_module_ranked( 'Arch' => arch, 'Platform' => platform) { |name, mod| encoders << [ name, mod ] } encoders end |
#encode ⇒ Object
Scans for a compatible encoder using ranked precedence and populates the encoded attribute.
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# File 'lib/msf/core/encoded_payload.rb', line 131 def encode # Get the minimum number of nops to use min = (reqs['MinNops'] || 0).to_i min = 0 if reqs['DisableNops'] # If the exploit needs the payload to be encoded, we need to run the list of # encoders in ranked precedence and try to encode with them. if needs_encoding # Make sure the encoder name from the user has the same String#encoding # as the framework's list of encoder names so we can compare them later. # This is important for when we get input from RPC. if reqs['Encoder'] reqs['Encoder'] = reqs['Encoder'].encode(framework.encoders.keys[0].encoding) end # If the caller had a preferred encoder, use this encoder only if ((reqs['Encoder']) and (preferred = framework.encoders[reqs['Encoder']])) encoders = [ [reqs['Encoder'], preferred] ] elsif (reqs['Encoder']) wlog("#{pinst.refname}: Failed to find preferred encoder #{reqs['Encoder']}") raise NoEncodersSucceededError, "Failed to find preferred encoder #{reqs['Encoder']}" else encoders = compatible_encoders end encoders.each { |encname, encmod| self.encoder = encmod.new self.encoded = nil # If the encoding is requested by an exploit check compatibility # options first of all. For the 'generic/none' encoder compatibility # options don't apply. if (reqs['Exploit'] && !reqs['Exploit'].compatible?(self.encoder) && encname !~ /generic\/none/) wlog("#{pinst.refname}: Encoder #{encoder.refname} doesn't match the exploit Compat options", 'core', LEV_1) next end # If there is an encoder type restriction, check to see if this # encoder matches with what we're searching for. if ((reqs['EncoderType']) and (self.encoder.encoder_type.split(/\s+/).include?(reqs['EncoderType']) == false)) wlog("#{pinst.refname}: Encoder #{encoder.refname} is not a compatible encoder type: #{reqs['EncoderType']} != #{self.encoder.encoder_type}", 'core', LEV_1) next end # If the exploit did not explicitly request a kind of encoder and # the current encoder has a manual ranking, then it should not be # considered as a valid encoder. A manual ranking tells the # framework that an encoder must be explicitly defined as the # encoder of choice for an exploit. if ((reqs['EncoderType'].nil?) and (reqs['Encoder'].nil?) and (self.encoder.rank == ManualRanking)) wlog("#{pinst.refname}: Encoder #{encoder.refname} is manual ranked and was not defined as a preferred encoder.", 'core', LEV_1) next end # If the caller explicitly requires register preservation, make sure # that the module in question can handle it. This is mostly used by # the stage encoder path. if (reqs['ForceSaveRegisters'] and reqs['EncoderOptions'] and (reqs['EncoderOptions']['SaveRegisters'].to_s.length > 0) and (! self.encoder.can_preserve_registers?)) wlog("#{pinst.refname}: Encoder #{encoder.refname} does not preserve registers and the caller needs #{reqs['EncoderOptions']['SaveRegisters']} preserved.", 'core', LEV_1) next end # Import the datastore from payload (and likely exploit by proxy) self.encoder.share_datastore(pinst.datastore) # If we have any encoder options, import them into the datastore # of the encoder. if (reqs['EncoderOptions']) self.encoder.datastore.(reqs['EncoderOptions']) end # Validate the encoder to make sure it's properly initialized. begin self.encoder.validate rescue ::Exception wlog("#{pinst.refname}: Failed to validate encoder #{encoder.refname}: #{$!}", 'core', LEV_1) next end # Tell the encoder how much space is available self.encoder.available_space = self.space eout = self.raw.dup next_encoder = false # Try encoding with the current encoder # # NOTE: Using more than one iteration may cause successive iterations to switch # to using a different encoder. # 1.upto(self.iterations) do |iter| err_start = "#{pinst.refname}: iteration #{iter}" begin eout = self.encoder.encode(eout, reqs['BadChars'], nil, pinst.platform) rescue EncodingError wlog("#{err_start}: Encoder #{encoder.refname} failed: #{$!}", 'core', LEV_1) dlog("#{err_start}: Call stack\n#{$@.join("\n")}", 'core', LEV_3) next_encoder = true break rescue ::Exception => e elog("Broken encoder #{encoder.refname}", error: e) next_encoder = true break end # Check to see if we have enough room for the minimum requirements if ((reqs['Space']) and (reqs['Space'] < eout.length + min)) wlog("#{err_start}: Encoded payload version is too large (#{eout.length} bytes) with encoder #{encoder.refname}", 'core', LEV_1) next_encoder = true break end ilog("#{err_start}: Successfully encoded with encoder #{encoder.refname} (size is #{eout.length})", 'core', LEV_0) end next if next_encoder self.encoded = eout break } # If the encoded payload is nil, raise an exception saying that we # suck at life. if (self.encoded == nil) self.encoder = nil raise NoEncodersSucceededError, "#{pinst.refname}: All encoders failed to encode.", caller end # If there are no bad characters, then the raw is the same as the # encoded else # NOTE: BadChars can contain whitespace, so don't use String#blank? unless reqs['BadChars'].nil? || reqs['BadChars'].empty? ilog("#{pinst.refname}: payload contains no badchars, skipping automatic encoding", 'core', LEV_0) end # Space = 0 is a special value used by msfvenom to generate the smallest # payload possible. In that case do not raise an exception indicating # that the payload is too large. if reqs['Space'] && reqs['Space'] > 0 && reqs['Space'] < raw.length + min wlog("#{pinst.refname}: Raw (unencoded) payload is too large (#{raw.length} bytes)", 'core', LEV_1) raise PayloadSpaceViolation, 'The payload exceeds the specified space', caller end self.encoded = raw end # Prefix the prepend encoder value self.encoded = (reqs['PrependEncoder'] || '') + self.encoded self.encoded << (reqs['AppendEncoder'] || '') end |
#encoded_exe(opts = {}) ⇒ Object
Convert the payload to an executable appropriate for its arch and platform.
opts
are passed directly to Msf::Util::EXE.to_executable
see Msf::Exploit::EXE
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# File 'lib/msf/core/encoded_payload.rb', line 399 def encoded_exe(opts={}) # Ensure arch and platform are in the format that to_executable expects if opts[:arch] and not opts[:arch].kind_of? Array opts[:arch] = [ opts[:arch] ] end if (opts[:platform].kind_of? Msf::Module::PlatformList) opts[:platform] = opts[:platform].platforms end emod = pinst.assoc_exploit if pinst.respond_to? :assoc_exploit if emod if (emod.datastore["EXE::Custom"] and emod.respond_to? :get_custom_exe) return emod.get_custom_exe end # This is a little ghetto, grabbing datastore options from the # associated exploit, but it doesn't really make sense for the # payload to have exe options if the exploit doesn't need an exe. # Msf::Util::EXE chooses reasonable defaults if these aren't given, # so it's not that big of an issue. opts.merge!({ :template_path => emod.datastore['EXE::Path'], :template => emod.datastore['EXE::Template'], :inject => emod.datastore['EXE::Inject'], :fallback => emod.datastore['EXE::FallBack'], :sub_method => emod.datastore['EXE::OldMethod'] }) # Prefer the target's platform/architecture information, but use # the exploit module's if no target specific information exists. opts[:platform] ||= emod.target_platform if emod.respond_to? :target_platform opts[:platform] ||= emod.platform if emod.respond_to? :platform opts[:arch] ||= emod.target_arch if emod.respond_to? :target_arch opts[:arch] ||= emod.arch if emod.respond_to? :arch end # Lastly, try the payload's. This always happens if we don't have an # associated exploit module. opts[:platform] ||= pinst.platform if pinst.respond_to? :platform opts[:arch] ||= pinst.arch if pinst.respond_to? :arch Msf::Util::EXE.to_executable(framework, opts[:arch], opts[:platform], encoded, opts) end |
#encoded_jar(opts = {}) ⇒ Object
Generate a jar file containing the encoded payload.
Uses the payload’s generate_jar
method if it is implemented (Java payloads should all have it). Otherwise, converts the payload to an executable and uses Msf::Util::EXE.to_jar to create a jar file that dumps the exe out to a random file name in the system’s temporary directory and executes it.
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# File 'lib/msf/core/encoded_payload.rb', line 450 def encoded_jar(opts={}) return pinst.generate_jar(opts) if pinst.respond_to? :generate_jar opts[:spawn] ||= pinst.datastore["Spawn"] Msf::Util::EXE.to_jar(encoded_exe(opts), opts) end |
#encoded_war(opts = {}) ⇒ Object
Similar to encoded_jar
but builds a web archive for use in servlet containers such as Tomcat.
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# File 'lib/msf/core/encoded_payload.rb', line 462 def encoded_war(opts={}) return pinst.generate_war(opts) if pinst.respond_to? :generate_war Msf::Util::EXE.to_jsp_war(encoded_exe(opts), opts) end |
#generate(raw = nil) ⇒ String
This method generates the full encoded payload and returns the encoded payload buffer.
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# File 'lib/msf/core/encoded_payload.rb', line 44 def generate(raw = nil) self.raw = raw self.encoded = nil self.nop_sled_size = 0 self.nop_sled = nil self.encoder = nil self.nop = nil # Increase thread priority as necessary. This is done # to ensure that the encoding and sled generation get # enough time slices from the ruby thread scheduler. priority = Thread.current.priority if (priority == 0) Thread.current.priority = 1 end begin # First, validate pinst.validate() # Propagate space information when set unless self.space.nil? # Tell the payload how much space is available pinst.available_space = self.space # Reserve 10% of the available space if encoding is required pinst.available_space -= (self.space * 0.1).ceil if needs_encoding end # Generate the raw version of the payload first generate_raw() if self.raw.nil? # If encoder is set, it could be an encoders list # The form is "<encoder>:<iteration>, <encoder2>:<iteration>"... unless reqs['Encoder'].blank? encoder_str = reqs['Encoder'] encoder_str.scan(/([^:, ]+):?([^,]+)?/).map do |encoder_opt| reqs['Encoder'] = encoder_opt[0] self.iterations = (encoder_opt[1] || reqs['Iterations']).to_i self.iterations = 1 if self.iterations < 1 # Encode the payload with every encoders in the list encode() # Encoded payload is now the raw payload to be encoded by the next encoder self.raw = self.encoded end else self.iterations = reqs['Iterations'].to_i self.iterations = 1 if self.iterations < 1 # No specified encoder, let BadChars or ForceEncode do their job encode() end # Build the NOP sled generate_sled() # Finally, set the complete payload definition self.encoded = (self.nop_sled || '') + self.encoded ensure # Restore the thread priority Thread.current.priority = priority end # Return the complete payload return encoded end |
#generate_raw ⇒ String
Generates the raw payload from the payload instance. This populates the #raw attribute.
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# File 'lib/msf/core/encoded_payload.rb', line 117 def generate_raw self.raw = (reqs['Prepend'] || '') + pinst.generate_complete + (reqs['Append'] || '') # If an encapsulation routine was supplied, then we should call it so # that we can get the real raw payload. if reqs['EncapsulationRoutine'] self.raw = reqs['EncapsulationRoutine'].call(reqs, raw) end end |
#generate_sled ⇒ Object
Construct a NOP sled if necessary
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# File 'lib/msf/core/encoded_payload.rb', line 306 def generate_sled min = reqs['MinNops'] || 0 space = reqs['Space'] pad_nops = reqs['PadNops'] self.nop_sled_size = min # Calculate the number of NOPs to pad out the buffer with based on the # requirements. If there was a space requirement, check to see if # there's any room at all left for a sled. if ((space) and (space > encoded.length)) self.nop_sled_size = reqs['Space'] - self.encoded.length end # If the maximum number of NOPs has been exceeded, wrap it back down. if ((reqs['MaxNops']) and (reqs['MaxNops'] < self.nop_sled_size)) self.nop_sled_size = reqs['MaxNops'] end # Check for the DisableNops setting self.nop_sled_size = 0 if reqs['DisableNops'] # Check for the PadNops setting self.nop_sled_size = (pad_nops - self.encoded.length) if reqs['PadNops'] # Now construct the actual sled if (self.nop_sled_size > 0) nops = pinst.compatible_nops # If the caller had a preferred nop, try to find it and prefix it if ((reqs['Nop']) and (preferred = framework.nops[reqs['Nop']])) nops.unshift([reqs['Nop'], preferred ]) elsif (reqs['Nop']) wlog("#{pinst.refname}: Failed to find preferred nop #{reqs['Nop']}") end nops.each { |nopname, nopmod| # Create an instance of the nop module self.nop = nopmod.new # Propagate options from the payload and possibly exploit self.nop.share_datastore(pinst.datastore) # The list of save registers save_regs = (reqs['SaveRegisters'] || []) + (pinst.save_registers || []) if (save_regs.empty? == true) save_regs = nil end begin nop.copy_ui(pinst) self.nop_sled = nop.generate_sled(self.nop_sled_size, 'BadChars' => reqs['BadChars'], 'SaveRegisters' => save_regs) if nop_sled && nop_sled.length == nop_sled_size break else dlog("#{pinst.refname}: Nop generator #{nop.refname} failed to generate sled for payload", 'core', LEV_1) end rescue dlog("#{pinst.refname}: Nop generator #{nop.refname} failed to generate sled for payload: #{$!}", 'core', LEV_1) self.nop = nil end } if (self.nop_sled == nil) raise NoNopsSucceededError, "#{pinst.refname}: All NOP generators failed to construct sled for.", caller end else self.nop_sled = '' end return self.nop_sled end |
#has_chars?(chars) ⇒ Boolean (protected)
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# File 'lib/msf/core/encoded_payload.rb', line 544 def has_chars?(chars) # NOTE: BadChars can contain whitespace, so don't use String#blank? if chars.nil? || chars.empty? return false end # payload hasn't been set yet but we have bad characters so assume they'll need to be encoded return true if self.raw.nil? return false if self.raw.empty? chars.each_byte do |bad| return true if self.raw.index(bad.chr(::Encoding::ASCII_8BIT)) end false end |
#needs_encoding ⇒ Object (protected)
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# File 'lib/msf/core/encoded_payload.rb', line 540 def needs_encoding !reqs['Encoder'].blank? || reqs['ForceEncode'] || has_chars?(reqs['BadChars']) end |
#platform ⇒ Object
An array containing the platform(s) that this payload was made to run on
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# File 'lib/msf/core/encoded_payload.rb', line 480 def platform if pinst pinst.platform end end |