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

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, #monitor_socket, #monitor_stop, #notify_response_waiter, #receive_packet, #register_inbound_handler, #remove_response_waiter, #send_packet, #send_packet_wait_response, #send_request

Constructor Details

#initialize(sock, opts = {}) ⇒ Client

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



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# 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.



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# File 'lib/rex/post/meterpreter/client.rb', line 234

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



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# File 'lib/rex/post/meterpreter/client.rb', line 348

def alive
  @alive
end

#capabilities ⇒ Object

The libraries available to this meterpreter server



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# File 'lib/rex/post/meterpreter/client.rb', line 356

def capabilities
  @capabilities
end

#ext ⇒ Object

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

client.ext.stdapi



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# File 'lib/rex/post/meterpreter/client.rb', line 331

def ext
  @ext
end

#response_timeout ⇒ Object

The timeout value to use when waiting for responses.



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# File 'lib/rex/post/meterpreter/client.rb', line 339

def response_timeout
  @response_timeout
end

#send_keepalives ⇒ Object

Whether to send pings every so often to determine liveness.



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

def send_keepalives
  @send_keepalives
end

#sock ⇒ Object

The socket the client is communicating over.



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

def sock
  @sock
end

#target_id ⇒ Object

The unique target identifier for this payload



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# File 'lib/rex/post/meterpreter/client.rb', line 352

def target_id
  @target_id
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.



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# 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.



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# File 'lib/rex/post/meterpreter/client.rb', line 220

def Client.default_timeout
	return 300
end

.lookup_error(code) ⇒ Object

Lookup the error that occurred



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# 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.



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# 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..



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# File 'lib/rex/post/meterpreter/client.rb', line 248

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.



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# 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
end

#deregister_extension(name) ⇒ Object

Deregisters an extension alias of the supplied name.



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# File 'lib/rex/post/meterpreter/client.rb', line 278

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

#deregister_extension_alias(name) ⇒ Object

Deregisters a previously registered extension alias.



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# File 'lib/rex/post/meterpreter/client.rb', line 309

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

#dump_extension_tree ⇒ Object

Dumps the extension tree.



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# File 'lib/rex/post/meterpreter/client.rb', line 316

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.



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

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

#generate_ssl_context ⇒ Object 



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# File 'lib/rex/post/meterpreter/client.rb', line 152

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



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# File 'lib/rex/post/meterpreter/client.rb', line 97

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.response_timeout =  opts[:timeout] || self.class.default_timeout
	self.send_keepalives  = true


	# 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

#register_extension_alias(name, ext) ⇒ Object

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



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# File 'lib/rex/post/meterpreter/client.rb', line 293

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.



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# File 'lib/rex/post/meterpreter/client.rb', line 300

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

#swap_sock_plain_to_ssl ⇒ Object 



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# File 'lib/rex/post/meterpreter/client.rb', line 126

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)

	ssl.accept

	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 



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# File 'lib/rex/post/meterpreter/client.rb', line 143

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