Module: Msf::Handler::ReverseSctp

Includes:
Msf::Handler, Reverse, Msf::Handler::Reverse::Comm
Defined in:
lib/msf/core/handler/reverse_sctp.rb

Constant Summary

Constants included from Msf::Handler

Claimed, Unused

Instance Attribute Summary collapse

Attributes included from Msf::Handler

#exploit_config, #parent_payload, #pending_connections, #session_waiter_event, #sessions

Class Method Summary collapse

Instance Method Summary collapse

Methods included from Msf::Handler::Reverse::Comm

#select_comm, #via_string

Methods included from Reverse

#bind_addresses, #bind_port, #is_loopback_address?

Methods included from Msf::Handler

#add_handler, #create_session, #handle_connection, #handler, #handler_name, #interrupt_wait_for_session, #register_session, #wait_for_session, #wfs_delay

Instance Attribute Details

#conn_threads ⇒ Object (protected)

:nodoc:



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# File 'lib/msf/core/handler/reverse_sctp.rb', line 234

def conn_threads
  @conn_threads
end

#handler_thread ⇒ Object (protected)

:nodoc:



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# File 'lib/msf/core/handler/reverse_sctp.rb', line 233

def handler_thread
  @handler_thread
end

#listener_sock ⇒ Object (protected)

:nodoc:



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# File 'lib/msf/core/handler/reverse_sctp.rb', line 231

def listener_sock
  @listener_sock
end

#listener_thread ⇒ Object (protected)

:nodoc:



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# File 'lib/msf/core/handler/reverse_sctp.rb', line 232

def listener_thread
  @listener_thread
end

Class Method Details

.general_handler_type ⇒ Object

Returns the connection-described general handler type, in this case ‘reverse’.



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# File 'lib/msf/core/handler/reverse_sctp.rb', line 34

def self.general_handler_type
  "reverse"
end

.handler_type ⇒ Object

Returns the string representation of the handler type, in this case ‘reverse_sctp’.



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# File 'lib/msf/core/handler/reverse_sctp.rb', line 26

def self.handler_type
  "reverse_sctp"
end

Instance Method Details

#cleanup_handler ⇒ Object

Closes the listener socket if one was created.



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# File 'lib/msf/core/handler/reverse_sctp.rb', line 101

def cleanup_handler
  stop_handler

  # Kill any remaining handle_connection threads that might
  # be hanging around
  conn_threads.each do |thr|
    begin
      thr.kill
    rescue
      nil
    end
  end
end

#comm_string ⇒ Object 



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# File 'lib/msf/core/handler/reverse_sctp.rb', line 129

def comm_string
  if listener_sock.nil?
    "(setting up)"
  else
    via_string(listener_sock.client) if listener_sock.respond_to?(:client)
  end
end

#human_name ⇒ String

A string suitable for displaying to the user

Returns:

  • (String) 


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# File 'lib/msf/core/handler/reverse_sctp.rb', line 118

def human_name
  "reverse SCTP"
end

#initialize(info = {}) ⇒ Object

Initializes the reverse SCTP handler and ads the options that are required for all reverse SCTP payloads, like local host and local port.



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# File 'lib/msf/core/handler/reverse_sctp.rb', line 42

def initialize(info = {})
  super

  # XXX: Not supported by all modules
  register_advanced_options(
    [
      OptAddress.new(
        'ReverseListenerBindAddress',
        [ false, 'The specific IP address to bind to on the local system' ]
      ),
      OptBool.new(
        'ReverseListenerThreaded',
        [ true, 'Handle every connection in a new thread (experimental)', false ]
      )
    ] +
    Msf::Opt::stager_retry_options,
    Msf::Handler::ReverseSctp
  )

  self.conn_threads = []
end

#listener_uri(addr = ) ⇒ String

A URI describing where we are listening

Parameters:

  • addr (String) (defaults to: ) —

    the address that

Returns:

  • (String) —

    A URI of the form scheme://host:port/



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# File 'lib/msf/core/handler/reverse_sctp.rb', line 141

def listener_uri(addr = datastore['ReverseListenerBindAddress'])
  addr = datastore['LHOST'] if addr.nil? || addr.empty?
  uri_host = Rex::Socket.is_ipv6?(addr) ? "[#{addr}]" : addr
  "sctp://#{uri_host}:#{bind_port}"
end

#payload_uri ⇒ Object

A URI describing what the payload is configured to use for transport



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# File 'lib/msf/core/handler/reverse_sctp.rb', line 123

def payload_uri
  addr = datastore['LHOST']
  uri_host = Rex::Socket.is_ipv6?(addr) ? "[#{addr}]" : addr
  "sctp://#{uri_host}:#{datastore['LPORT']}"
end

#setup_handler ⇒ Object 



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# File 'lib/msf/core/handler/reverse_sctp.rb', line 64

def setup_handler
  if !datastore['Proxies'].blank? && !datastore['ReverseAllowProxy']
    raise RuntimeError, "SCTP connect-back payloads cannot be used with Proxies. Use 'set ReverseAllowProxy true' to override this behaviour."
  end

  ex = false

  comm = select_comm
  local_port = bind_port

  bind_addresses.each do |ip|
    begin
      self.listener_sock = Rex::Socket::SctpServer.create(
        'LocalHost' => ip,
        'LocalPort' => local_port,
        'Comm'      => comm,
        'Context'   =>
        {
          'Msf'        => framework,
          'MsfPayload' => self,
          'MsfExploit' => assoc_exploit
        })
    rescue
      ex = $!
      print_error("Handler failed to bind to #{ip}:#{local_port}:- #{comm} -")
    else
      ex = false
      via = via_string(self.listener_sock.client) if self.listener_sock.respond_to?(:client)
      print_status("Started #{human_name} handler on #{ip}:#{local_port} #{via}")
      break
    end
  end
  raise ex if (ex)
end

#start_handler ⇒ Object

Starts monitoring for an inbound connection.



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# File 'lib/msf/core/handler/reverse_sctp.rb', line 150

def start_handler
  queue = ::Queue.new

  local_port = bind_port

  handler_name = "ReverseSctpHandlerListener-#{local_port}"
  self.listener_thread = framework.threads.spawn(handler_name, false, queue) { |lqueue|
    loop do
      # Accept a client connection
      begin
        client = listener_sock.accept
        if client
          self.pending_connections += 1
          lqueue.push(client)
        end
      rescue Errno::ENOTCONN
        nil
      rescue StandardError => e
        wlog [
          "#{handler_name}: Exception raised during listener accept: #{e.class}",
          $ERROR_INFO.to_s,
          $ERROR_POSITION.join("\n")
        ].join("\n")
      end
    end
  }

  worker_name = "ReverseSctpHandlerWorker-#{local_port}"
  self.handler_thread = framework.threads.spawn(worker_name, false, queue) { |cqueue|
    loop do
      begin
        client = cqueue.pop

        unless client
          elog("#{worker_name}: Queue returned an empty result, exiting...")
        end

        # Timeout and datastore options need to be passed through to the client
        opts = {
          datastore:     datastore,
          expiration:    datastore['SessionExpirationTimeout'].to_i,
          comm_timeout:  datastore['SessionCommunicationTimeout'].to_i,
          retry_total:   datastore['SessionRetryTotal'].to_i,
          retry_wait:    datastore['SessionRetryWait'].to_i
        }

        if datastore['ReverseListenerThreaded']
          thread_name = "#{worker_name}-#{client.peerhost}"
          conn_threads << framework.threads.spawn(thread_name, false, client) do |client_copy|
            handle_connection(client_copy, opts)
          end
        else
          handle_connection(client, opts)
        end
      rescue StandardError => e
        elog('Exception raised from handle_connection', error: e)
      end
    end
  }
end

#stop_handler ⇒ Object

Stops monitoring for an inbound connection.



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# File 'lib/msf/core/handler/reverse_sctp.rb', line 214

def stop_handler
  # Terminate the listener thread
  listener_thread.kill if listener_thread && listener_thread.alive? == true

  # Terminate the handler thread
  handler_thread.kill if handler_thread && handler_thread.alive? == true

  begin
    listener_sock.close if listener_sock
  rescue IOError
    # Ignore if it's listening on a dead session
    dlog("IOError closing listener sock; listening on dead session?", LEV_1)
  end
end