Module: Msf::Exploit::Remote::Tcp

Overview

This module provides methods for establish a connection to a remote host and communicating with it.

Instance Attribute Summary collapse

Instance Method Summary collapse

Instance Attribute Details

#sockObject (protected)

Returns the value of attribute sock


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# File 'lib/msf/core/exploit/remote/tcp.rb', line 318

def sock
  @sock
end

Instance Method Details

#chostObject

Returns the local host for outgoing connections


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# File 'lib/msf/core/exploit/remote/tcp.rb', line 230

def chost
  datastore['CHOST']
end

#cleanupObject

Performs cleanup, disconnects the socket if necessary


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# File 'lib/msf/core/exploit/remote/tcp.rb', line 204

def cleanup
  super
  disconnect
end

#connect(global = true, opts = {}) ⇒ Object

Establishes a TCP connection to the specified RHOST/RPORT

See Also:

  • Rex::Socket::Tcp
  • Rex::Socket::Tcp.create

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# File 'lib/msf/core/exploit/remote/tcp.rb', line 93

def connect(global = true, opts={})

  dossl = false
  if(opts.has_key?('SSL'))
    dossl = opts['SSL']
  else
    dossl = ssl
    if (datastore.default?('SSL') and rport.to_i == 443)
      dossl = true
    end
  end

  nsock = Rex::Socket::Tcp.create(
    'PeerHost'      =>  opts['RHOST'] || rhost,
    'PeerPort'      => (opts['RPORT'] || rport).to_i,
    'LocalHost'     =>  opts['CHOST'] || chost || "0.0.0.0",
    'LocalPort'     => (opts['CPORT'] || cport || 0).to_i,
    'SSL'           =>  dossl,
    'SSLVersion'    =>  opts['SSLVersion'] || ssl_version,
    'SSLVerifyMode' =>  opts['SSLVerifyMode'] || ssl_verify_mode,
    'SSLCipher'     =>  opts['SSLCipher'] || ssl_cipher,
    'Proxies'       => proxies,
    'Timeout'       => (opts['ConnectTimeout'] || connect_timeout || 10).to_i,
    'Context'       =>
      {
        'Msf'        => framework,
        'MsfExploit' => self,
      })

  # enable evasions on this socket
  set_tcp_evasions(nsock)

  # Set this socket to the global socket as necessary
  self.sock = nsock if (global)

  # Add this socket to the list of sockets created by this exploit
  add_socket(nsock)

  return nsock
end

#connect_timeoutObject

Returns the TCP connection timeout


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# File 'lib/msf/core/exploit/remote/tcp.rb', line 237

def connect_timeout
  datastore['ConnectTimeout']
end

#cportObject

Returns the local port for outgoing connections


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# File 'lib/msf/core/exploit/remote/tcp.rb', line 244

def cport
  datastore['CPORT']
end

#deregister_tcp_optionsObject


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# File 'lib/msf/core/exploit/remote/tcp.rb', line 84

def deregister_tcp_options
  deregister_options('RHOST', 'RPORT')
end

#disconnect(nsock = self.sock) ⇒ Object

Closes the TCP connection


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# File 'lib/msf/core/exploit/remote/tcp.rb', line 184

def disconnect(nsock = self.sock)
  begin
    if (nsock)
      nsock.shutdown
      nsock.close
    end
  rescue IOError
  end

  if (nsock == sock)
    self.sock = nil
  end

  # Remove this socket from the list of sockets created by this exploit
  remove_socket(nsock)
end

#handler(nsock = self.sock) ⇒ Object


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# File 'lib/msf/core/exploit/remote/tcp.rb', line 157

def handler(nsock = self.sock)
  # If the handler claims the socket, then we don't want it to get closed
  # during cleanup
  if ((rv = super) == Handler::Claimed)
    if (nsock == self.sock)
      self.sock = nil
    end

    # Remove this socket from the list of sockets so that it will not be
    # aborted.
    remove_socket(nsock)
  end

  return rv
end

#initialize(info = {}) ⇒ Object

Initializes an instance of an exploit module that exploits a vulnerability in a TCP server.


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# File 'lib/msf/core/exploit/remote/tcp.rb', line 53

def initialize(info = {})
  super

  register_options(
    [
      Opt::RHOST,
      Opt::RPORT
    ], Msf::Exploit::Remote::Tcp
  )

  register_advanced_options(
    [
      OptBool.new('SSL',        [ false, 'Negotiate SSL/TLS for outgoing connections', false]),
      Opt::SSLVersion,
      OptEnum.new('SSLVerifyMode',  [ false, 'SSL verification method', 'PEER', %W{CLIENT_ONCE FAIL_IF_NO_PEER_CERT NONE PEER}]),
      OptString.new('SSLCipher',    [ false, 'String for SSL cipher - "DHE-RSA-AES256-SHA" or "ADH"']),
      Opt::Proxies,
      Opt::CPORT,
      Opt::CHOST,
      OptInt.new('ConnectTimeout', [ true, 'Maximum number of seconds to establish a TCP connection', 10])
    ], Msf::Exploit::Remote::Tcp
  )

  register_evasion_options(
    [
      OptInt.new('TCP::max_send_size', [false, 'Maxiumum tcp segment size.  (0 = disable)', 0]),
      OptInt.new('TCP::send_delay', [false, 'Delays inserted before every send.  (0 = disable)', 0])
    ], Msf::Exploit::Remote::Tcp
  )
end

#lhostObject

Returns the local host


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# File 'lib/msf/core/exploit/remote/tcp.rb', line 251

def lhost
  datastore['LHOST']
end

#lportObject

Returns the local port


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# File 'lib/msf/core/exploit/remote/tcp.rb', line 258

def lport
  datastore['LPORT']
end

#peerObject

Returns the rhost:rport


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# File 'lib/msf/core/exploit/remote/tcp.rb', line 263

def peer
  "#{rhost}:#{rport}"
end

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# File 'lib/msf/core/exploit/remote/tcp.rb', line 209

def print_prefix
  # Only inject a host/port prefix if we have exactly one entry.
  # Otherwise we are logging in the global context where rhost can be any
  # size (being an alias for rhosts), which is not very useful to insert into
  # a single log line.
  if rhost && rhost.split(' ').length == 1
    super + peer + ' - '
  else
    super
  end
end

#proxiesObject

Returns the proxy configuration


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# File 'lib/msf/core/exploit/remote/tcp.rb', line 270

def proxies
  datastore['Proxies']
end

#rhostObject

Returns the target host


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# File 'lib/msf/core/exploit/remote/tcp.rb', line 277

def rhost
  datastore['RHOST']
end

#rportObject

Returns the remote port


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# File 'lib/msf/core/exploit/remote/tcp.rb', line 284

def rport
  datastore['RPORT']
end

#set_tcp_evasions(socket) ⇒ Object

Enable evasions on a given client


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# File 'lib/msf/core/exploit/remote/tcp.rb', line 135

def set_tcp_evasions(socket)

  if( datastore['TCP::max_send_size'].to_i == 0 and datastore['TCP::send_delay'].to_i == 0)
    return
  end

  return if socket.respond_to?('evasive')

  socket.extend(EvasiveTCP)

  if ( datastore['TCP::max_send_size'].to_i > 0)
    socket._send_size = datastore['TCP::max_send_size']
    socket.denagle
    socket.evasive = true
  end

  if ( datastore['TCP::send_delay'].to_i > 0)
    socket._send_delay = datastore['TCP::send_delay']
    socket.evasive = true
  end
end

#shutdown(how = :SHUT_RDWR) ⇒ Object

Shutdown the TCP connection


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# File 'lib/msf/core/exploit/remote/tcp.rb', line 176

def shutdown(how = :SHUT_RDWR)
  self.sock.shutdown(how) if self.sock
rescue IOError
end

#sslObject

Returns the boolean indicating SSL


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# File 'lib/msf/core/exploit/remote/tcp.rb', line 291

def ssl
  datastore['SSL']
end

#ssl_cipherObject

Returns the SSL cipher to use for the context


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# File 'lib/msf/core/exploit/remote/tcp.rb', line 312

def ssl_cipher
  datastore['SSLCipher']
end

#ssl_verify_modeObject

Returns the SSL certification verification mechanism


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# File 'lib/msf/core/exploit/remote/tcp.rb', line 305

def ssl_verify_mode
  datastore['SSLVerifyMode']
end

#ssl_versionObject

Returns the string indicating SSLVersion


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# File 'lib/msf/core/exploit/remote/tcp.rb', line 298

def ssl_version
  datastore['SSLVersion']
end