Class: Rex::Post::Meterpreter::Client

Inherits:
Object
  • Object
show all
Includes:
ChannelContainer, PacketDispatcher
Defined in:
lib/rex/post/meterpreter/client.rb

Overview

This class represents a logical meterpreter client class. This class provides an interface that is compatible with the Rex post-exploitation interface in terms of the feature set that it attempts to expose. This class is meant to drive a single meterpreter client session.

Constant Summary collapse

@@ext_hash =

Extension name to class hash.

{}
@@ssl_ctx =

Cached SSL certificate (required to scale)

nil
@@ssl_mutex =

Mutex to synchronize class-wide operations

::Mutex.new

Constants included from PacketDispatcher

PacketDispatcher::PacketTimeout

Instance Attribute Summary collapse

Attributes included from ChannelContainer

#channels

Attributes included from PacketDispatcher

#comm_mutex, #passive_service, #recv_queue, #send_queue

Class Method Summary collapse

Instance Method Summary collapse

Methods included from ChannelContainer

#add_channel, #find_channel, #initialize_channels, #remove_channel

Methods included from PacketDispatcher

#add_response_waiter, #deregister_inbound_handler, #dispatch_inbound_packet, #initialize_inbound_handlers, #initialize_passive_dispatcher, #monitor_socket, #monitor_stop, #notify_response_waiter, #on_passive_request, #receive_packet, #register_inbound_handler, #remove_response_waiter, #send_packet, #send_packet_wait_response, #send_request, #shutdown_passive_dispatcher

Constructor Details

#initialize(sock, opts = {}) ⇒ Client

Initializes the client context with the supplied socket through which communication with the server will be performed.



80
81
82
 
# File 'lib/rex/post/meterpreter/client.rb', line 80

def initialize(sock,opts={})
	init_meterpreter(sock, opts)
end

Dynamic Method Handling

This class handles dynamic methods through the method_missing method

#method_missing(symbol, *args) ⇒ Object

Translates unhandled methods into registered extension aliases if a matching extension alias exists for the supplied symbol.



283
284
285
 
# File 'lib/rex/post/meterpreter/client.rb', line 283

def method_missing(symbol, *args)
	self.ext_aliases.aliases[symbol.to_s]
end

Instance Attribute Details

#alive ⇒ Object

Whether this session is alive. If the socket is disconnected or broken, this will be false



411
412
413
 
# File 'lib/rex/post/meterpreter/client.rb', line 411

def alive
  @alive
end

#capabilities ⇒ Object

The libraries available to this meterpreter server



419
420
421
 
# File 'lib/rex/post/meterpreter/client.rb', line 419

def capabilities
  @capabilities
end

#comm_timeout ⇒ Object

The Communication Timeout



439
440
441
 
# File 'lib/rex/post/meterpreter/client.rb', line 439

def comm_timeout
  @comm_timeout
end

#conn_id ⇒ Object

The Connection ID



423
424
425
 
# File 'lib/rex/post/meterpreter/client.rb', line 423

def conn_id
  @conn_id
end

#encode_unicode ⇒ Object

Flag indicating whether to hex-encode UTF-8 file names and other strings



447
448
449
 
# File 'lib/rex/post/meterpreter/client.rb', line 447

def encode_unicode
  @encode_unicode
end

#expiration ⇒ Object

The Session Expiration Timeout



435
436
437
 
# File 'lib/rex/post/meterpreter/client.rb', line 435

def expiration
  @expiration
end

#ext ⇒ Object

The extension alias under which all extensions can be accessed by name. For example:

client.ext.stdapi



394
395
396
 
# File 'lib/rex/post/meterpreter/client.rb', line 394

def ext
  @ext
end

#passive_dispatcher ⇒ Object

The Passive Dispatcher



443
444
445
 
# File 'lib/rex/post/meterpreter/client.rb', line 443

def passive_dispatcher
  @passive_dispatcher
end

#response_timeout ⇒ Object

The timeout value to use when waiting for responses.



402
403
404
 
# File 'lib/rex/post/meterpreter/client.rb', line 402

def response_timeout
  @response_timeout
end

#send_keepalives ⇒ Object

Whether to send pings every so often to determine liveness.



406
407
408
 
# File 'lib/rex/post/meterpreter/client.rb', line 406

def send_keepalives
  @send_keepalives
end

#sock ⇒ Object

The socket the client is communicating over.



398
399
400
 
# File 'lib/rex/post/meterpreter/client.rb', line 398

def sock
  @sock
end

#ssl ⇒ Object

Use SSL (HTTPS)



431
432
433
 
# File 'lib/rex/post/meterpreter/client.rb', line 431

def ssl
  @ssl
end

#target_id ⇒ Object

The unique target identifier for this payload



415
416
417
 
# File 'lib/rex/post/meterpreter/client.rb', line 415

def target_id
  @target_id
end

#url ⇒ Object

The Connect URL



427
428
429
 
# File 'lib/rex/post/meterpreter/client.rb', line 427

def url
  @url
end

Class Method Details

.check_ext_hash(name) ⇒ Object

Checks the extension hash to see if a class has already been associated with the supplied extension name.



65
66
67
 
# File 'lib/rex/post/meterpreter/client.rb', line 65

def self.check_ext_hash(name)
	@@ext_hash[name]
end

.default_timeout ⇒ Object

Returns the default timeout that request packets will use when waiting for a response.



269
270
271
 
# File 'lib/rex/post/meterpreter/client.rb', line 269

def Client.default_timeout
	return 300
end

.lookup_error(code) ⇒ Object

Lookup the error that occurred



57
58
59
 
# File 'lib/rex/post/meterpreter/client.rb', line 57

def self.lookup_error(code)
	code
end

.set_ext_hash(name, klass) ⇒ Object

Stores the name to class association for the supplied extension name.



72
73
74
 
# File 'lib/rex/post/meterpreter/client.rb', line 72

def self.set_ext_hash(name, klass)
	@@ext_hash[name] = klass
end

Instance Method Details

#add_extension(name) ⇒ Object

Loads the client half of the supplied extension and initializes it as a registered extension that can be reached through client.ext..



297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
 
# File 'lib/rex/post/meterpreter/client.rb', line 297

def add_extension(name)
	# Check to see if this extension has already been loaded.
	if ((klass = self.class.check_ext_hash(name.downcase)) == nil)
		old = Rex::Post::Meterpreter::Extensions.constants
		require("rex/post/meterpreter/extensions/#{name.downcase}/#{name.downcase}")
		new = Rex::Post::Meterpreter::Extensions.constants

		# No new constants added?
		if ((diff = new - old).empty?)
			diff = [ name.capitalize ]
		end

		klass = Rex::Post::Meterpreter::Extensions.const_get(diff[0]).const_get(diff[0])

		# Save the module name to class association now that the code is
		# loaded.
		self.class.set_ext_hash(name.downcase, klass)
	end

	# Create a new instance of the extension
	inst = klass.new(self)

	self.ext.aliases[inst.name] = inst

	return true
end

#cleanup_meterpreter ⇒ Object

Cleans up the meterpreter instance, terminating the dispatcher thread.



87
88
89
90
91
92
93
94
 
# File 'lib/rex/post/meterpreter/client.rb', line 87

def cleanup_meterpreter
	ext.aliases.each_value do | extension |
		extension.cleanup if extension.respond_to?( 'cleanup' )
	end
	dispatcher_thread.kill if dispatcher_thread
	core.shutdown rescue nil
	shutdown_passive_dispatcher
end

#deregister_extension(name) ⇒ Object

Deregisters an extension alias of the supplied name.



327
328
329
 
# File 'lib/rex/post/meterpreter/client.rb', line 327

def deregister_extension(name)
	self.ext.aliases.delete(name)
end

#deregister_extension_alias(name) ⇒ Object

Deregisters a previously registered extension alias.



358
359
360
 
# File 'lib/rex/post/meterpreter/client.rb', line 358

def deregister_extension_alias(name)
	self.ext_aliases.aliases.delete(name)
end

#dump_extension_tree ⇒ Object

Dumps the extension tree.



365
366
367
368
369
370
371
 
# File 'lib/rex/post/meterpreter/client.rb', line 365

def dump_extension_tree()
	items = []
	items.concat(self.ext.dump_alias_tree('client.ext'))
	items.concat(self.ext_aliases.dump_alias_tree('client'))

	return items.sort
end

#each_extension(&block) ⇒ Object

Enumerates all of the loaded extensions.



334
335
336
 
# File 'lib/rex/post/meterpreter/client.rb', line 334

def each_extension(&block)
	self.ext.aliases.each(block)
end

#generate_ssl_context ⇒ Object 



201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
 
# File 'lib/rex/post/meterpreter/client.rb', line 201

def generate_ssl_context
	@@ssl_mutex.synchronize do
	if not @@ssl_ctx

	wlog("Generating SSL certificate for Meterpreter sessions")

	key  = OpenSSL::PKey::RSA.new(1024){ }
	cert = OpenSSL::X509::Certificate.new
	cert.version = 2
	cert.serial  = rand(0xFFFFFFFF)

	subject = OpenSSL::X509::Name.new([
			["C","US"],
			['ST', Rex::Text.rand_state()],
			["L", Rex::Text.rand_text_alpha(rand(20) + 10)],
			["O", Rex::Text.rand_text_alpha(rand(20) + 10)],
			["CN", self.sock.getsockname[1] || Rex::Text.rand_hostname],
		])
	issuer = OpenSSL::X509::Name.new([
			["C","US"],
			['ST', Rex::Text.rand_state()],
			["L", Rex::Text.rand_text_alpha(rand(20) + 10)],
			["O", Rex::Text.rand_text_alpha(rand(20) + 10)],
			["CN", Rex::Text.rand_text_alpha(rand(20) + 10)],
		])

	cert.subject = subject
	cert.issuer = issuer
	cert.not_before = Time.now - (3600 * 365) + rand(3600 * 14)
	cert.not_after = Time.now + (3600 * 365) + rand(3600 * 14)
	cert.public_key = key.public_key
	ef = OpenSSL::X509::ExtensionFactory.new(nil,cert)
	cert.extensions = [
		ef.create_extension("basicConstraints","CA:FALSE"),
		ef.create_extension("subjectKeyIdentifier","hash"),
		ef.create_extension("extendedKeyUsage","serverAuth"),
		ef.create_extension("keyUsage","keyEncipherment,dataEncipherment,digitalSignature")
	]
	ef.issuer_certificate = cert
	cert.add_extension ef.create_extension("authorityKeyIdentifier", "keyid:always,issuer:always")
	cert.sign(key, OpenSSL::Digest::SHA1.new)

	ctx = OpenSSL::SSL::SSLContext.new(:SSLv3)
	ctx.key = key
	ctx.cert = cert

	ctx.session_id_context = Rex::Text.rand_text(16)

	wlog("Generated SSL certificate for Meterpreter sessions")

	@@ssl_ctx = ctx

	end # End of if not @ssl_ctx
	end # End of mutex.synchronize

	@@ssl_ctx
end

#init_meterpreter(sock, opts = {}) ⇒ Object

Initializes the meterpreter client instance



99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
 
# File 'lib/rex/post/meterpreter/client.rb', line 99

def init_meterpreter(sock,opts={})
	self.sock         = sock
	self.parser       = PacketParser.new
	self.ext          = ObjectAliases.new
	self.ext_aliases  = ObjectAliases.new
	self.alive        = true
	self.target_id    = opts[:target_id]
	self.capabilities = opts[:capabilities] || {}


	self.conn_id      = opts[:conn_id]
	self.url          = opts[:url]
	self.ssl          = opts[:ssl]
	self.expiration   = opts[:expiration]
	self.comm_timeout = opts[:comm_timeout]
	self.passive_dispatcher = opts[:passive_dispatcher]

	self.response_timeout = opts[:timeout] || self.class.default_timeout
	self.send_keepalives  = true
	# self.encode_unicode   = opts.has_key?(:encode_unicode) ? opts[:encode_unicode] : true
	self.encode_unicode = false

	if opts[:passive_dispatcher]
		initialize_passive_dispatcher

		register_extension_alias('core', ClientCore.new(self))

		initialize_inbound_handlers
		initialize_channels

		# Register the channel inbound packet handler
		register_inbound_handler(Rex::Post::Meterpreter::Channel)
	else
		# Switch the socket to SSL mode and receive the hello if needed
		if capabilities[:ssl] and not opts[:skip_ssl]
			swap_sock_plain_to_ssl()
		end

		register_extension_alias('core', ClientCore.new(self))

		initialize_inbound_handlers
		initialize_channels

		# Register the channel inbound packet handler
		register_inbound_handler(Rex::Post::Meterpreter::Channel)

		monitor_socket
	end
end

#register_extension_alias(name, ext) ⇒ Object

Registers an aliased extension that can be referenced through client.name.



342
343
344
 
# File 'lib/rex/post/meterpreter/client.rb', line 342

def register_extension_alias(name, ext)
	self.ext_aliases.aliases[name] = ext
end

#register_extension_aliases(aliases) ⇒ Object

Registers zero or more aliases that are provided in an array.



349
350
351
352
353
 
# File 'lib/rex/post/meterpreter/client.rb', line 349

def register_extension_aliases(aliases)
	aliases.each { |a|
		register_extension_alias(a['name'], a['ext'])
	}
end

#swap_sock_plain_to_ssl ⇒ Object 



149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
 
# File 'lib/rex/post/meterpreter/client.rb', line 149

def swap_sock_plain_to_ssl
	# Create a new SSL session on the existing socket
	ctx = generate_ssl_context()
	ssl = OpenSSL::SSL::SSLSocket.new(sock, ctx)

	# Use non-blocking OpenSSL operations on Windows
	if not ( ssl.respond_to?(:accept_nonblock) and Rex::Compat.is_windows )
		ssl.accept
	else
		begin
			ssl.accept_nonblock

		# Ruby 1.8.7 and 1.9.0/1.9.1 uses a standard Errno
		rescue ::Errno::EAGAIN, ::Errno::EWOULDBLOCK
				IO::select(nil, nil, nil, 0.10)
				retry

		# Ruby 1.9.2+ uses IO::WaitReadable/IO::WaitWritable
		rescue ::Exception => e
			if ::IO.const_defined?('WaitReadable') and e.kind_of?(::IO::WaitReadable)
				IO::select( [ ssl ], nil, nil, 0.10 )
				retry
			end

			if ::IO.const_defined?('WaitWritable') and e.kind_of?(::IO::WaitWritable)
				IO::select( nil, [ ssl ], nil, 0.10 )
				retry
			end

			raise e
		end
	end

	self.sock.extend(Rex::Socket::SslTcp)
	self.sock.sslsock = ssl
	self.sock.sslctx  = ctx

	tag = self.sock.get_once(-1, 30)
	if(not tag or tag !~ /^GET \//)
		raise RuntimeError, "Could not read the HTTP hello token"
	end
end

#swap_sock_ssl_to_plain ⇒ Object 



192
193
194
195
196
197
198
199
 
# File 'lib/rex/post/meterpreter/client.rb', line 192

def swap_sock_ssl_to_plain
	# Remove references to the SSLSocket and Context
	self.sock.sslsock.close
	self.sock.sslsock = nil
	self.sock.sslctx  = nil
	self.sock = self.sock.fd
	self.sock.extend(::Rex::Socket::Tcp)
end

#unicode_filter_decode(str) ⇒ Object

Decodes (or not) a UTF-8 string



383
384
385
 
# File 'lib/rex/post/meterpreter/client.rb', line 383

def unicode_filter_decode(str)
	self.encode_unicode ? Rex::Text.unicode_filter_decode(str) : str
end

#unicode_filter_encode(str) ⇒ Object

Encodes (or not) a UTF-8 string



376
377
378
 
# File 'lib/rex/post/meterpreter/client.rb', line 376

def unicode_filter_encode(str)
	self.encode_unicode ? Rex::Text.unicode_filter_encode(str) : str
end