Module: Msf::Exploit::Remote::FtpServer

Includes:
TcpServer
Defined in:
lib/msf/core/exploit/ftpserver.rb

Overview

This module exposes methods that may be useful to exploits that deal with clients that speak the File Transfer Protocol (FTP).

Instance Method Summary collapse

Methods included from TcpServer

#cleanup, #exploit, #primer, #regenerate_payload, #srvhost, #srvport, #ssl, #ssl_cert, #ssl_compression, #start_service, #stop_service

Instance Method Details

#active_data_port_for_client(c, port) ⇒ Object


189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
# File 'lib/msf/core/exploit/ftpserver.rb', line 189

def active_data_port_for_client(c,port)
  @state[c][:mode] = :active

  connector = Proc.new {
    host = c.peerhost.dup
    sock = Rex::Socket::Tcp.create(
      'PeerHost' => host,
      'PeerPort' => port,
      'Context'   => { 'Msf' => framework, 'MsfExploit' => self }
    )
    add_socket(sock)
    sock
  }

  @state[c][:active_connector] = connector
  @state[c][:active_port]      = port
end

#establish_data_connection(c) ⇒ Socket?

Create a socket for the protocol data, either PASV or PORT, depending on the client.

Parameters:

  • c (Socket)

    Control connection socket

Returns:

  • (Socket)

    A connected socket for the data connection

  • (nil)

    on failure

See Also:


217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
# File 'lib/msf/core/exploit/ftpserver.rb', line 217

def establish_data_connection(c)
  begin
  Timeout.timeout(20) do
    if(@state[c][:mode] == :active)
      return @state[c][:active_connector].call()
    end
    if(@state[c][:mode] == :passive)
      c = @state[c][:passive_sock].accept
      add_socket(c)
      return c
    end
  end

  rescue ::Exception => e
    print_error("Failed to establish data connection: #{e.class} #{e}")
  end

  nil
end

#initialize(info = {}) ⇒ Object

Creates an instance of an FTP exploit module.


19
20
21
22
23
24
25
26
27
# File 'lib/msf/core/exploit/ftpserver.rb', line 19

def initialize(info = {})
  super

  # Register the options that all FTP exploits may make use of.
  register_options(
    [
      OptPort.new('SRVPORT',    [ true, "The local port to listen on.", 21 ])
    ], Msf::Exploit::Remote::FtpServer)
end

#on_client_close(c) ⇒ Object


165
166
167
# File 'lib/msf/core/exploit/ftpserver.rb', line 165

def on_client_close(c)
  @state.delete(c)
end

#on_client_connect(c) ⇒ Object

Called when a client connects.


36
37
38
39
40
41
42
43
44
45
46
47
48
49
# File 'lib/msf/core/exploit/ftpserver.rb', line 36

def on_client_connect(c)
  @state[c] = {
    :name => "#{c.peerhost}:#{c.peerport}",
    :ip   => c.peerhost,
    :port => c.peerport,
    :user => nil,
    :pass => nil,
    :cwd  => '/'
  }

  active_data_port_for_client(c, 20)

  c.put "220 FTP Server Ready\r\n"
end

#on_client_data(c) ⇒ Object

Dispatches client requests to command handlers.

Handlers should be named on_client_command_*, ending with a downcased FTP verb, e.g. on_client_command_user. If no handler exists for the given command, returns a generic default response.

Examples:

Handle SYST requests

class Metasploit4 < Msf::Exploit
  include Msf::Exploit::Remote::FtpServer
  ...
  def on_client_command_syst(cmd_conn, arg)
    print_status("Responding to SYST request")
    buf = build_exploit_buffer(cmd_conn)
    cmd_conn.put("215 Unix Type: #{buf}\r\n")
  end
end

70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
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
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
# File 'lib/msf/core/exploit/ftpserver.rb', line 70

def on_client_data(c)
  data = c.get_once
  return if not data

  cmd,arg = data.strip.split(/\s+/, 2)
  arg ||= ""

  return if not cmd

  # Allow per-command overrides
  if(self.respond_to?("on_client_command_#{cmd.downcase}"))
    return self.send("on_client_command_#{cmd.downcase}", c, arg)
  end

  case cmd.upcase
  when 'USER'
    @state[c][:user] = arg
    c.put "331 User name okay, need password...\r\n"
    return

  when 'PASS'
    @state[c][:pass] = arg
    print_status("#{@state[c][:name]} LOGIN #{@state[c][:user]} / #{@state[c][:pass]}")
    c.put "230 Login OK\r\n"
    return

  when 'QUIT'
    c.put "221 Logout\r\n"
    return

  when 'SYST'
    c.put "215 UNIX Type: L8\r\n"
    return

  when 'TYPE'
    c.put "200 Type is set\r\n"
    return

  when 'CWD'
    c.put "250 CWD command successful.\r\n"
    return

  when 'PWD'
    c.put "257 \"#{@state[c][:cwd]}\" is current directory.\r\n"
    return

  when 'SIZE'
    c.put "213 1\r\n"
    return

  when 'MDTM'
    c.put "213 #{Time.now.strftime("%Y%m%d%H%M%S")}\r\n"
    return

  when 'PORT'
    port = arg.split(',')[4,2]
    if(not port and port.length == 2)
      c.put("500 Illegal PORT command.\r\n")
      return
    end

    port = port.map{|x| x.to_i}.pack('C*').unpack('n')[0]
    active_data_port_for_client(c, port)

    c.put "200 PORT command successful.\r\n"
    return

  when 'PASV'
    daddr = Rex::Socket.source_address(c.peerhost)
    dport = passive_data_port_for_client(c)
    @state[c][:daddr] = daddr
    @state[c][:dport] = dport
    pasv  = (daddr.split('.') + [dport].pack('n').unpack('CC')).join(',')
    c.put "227 Entering Passive Mode (#{pasv})\r\n"
    return

  when /^(STOR|MKD|REM|DEL|RMD)$/
    c.put "500 Access denied\r\n"
    return

  else
    # Allow per-command overrides
    if(self.respond_to?("on_client_unknown_command"))
      return self.send("on_client_unknown_command", c, cmd.upcase, arg)
    end

    print_status("#{@state[c][:name]} UNKNOWN '#{cmd} #{arg}'")
    c.put("500 '#{cmd} #{arg}': command not understood.\r\n")
    return
  end

  return

end

#passive_data_port_for_client(c) ⇒ Object


169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
# File 'lib/msf/core/exploit/ftpserver.rb', line 169

def passive_data_port_for_client(c)
  @state[c][:mode] = :passive

  if(not @state[c][:passive_sock])
    s = Rex::Socket::TcpServer.create(
      'LocalHost' => '0.0.0.0',
      'LocalPort' => 0,
      'Context'   => { 'Msf' => framework, 'MsfExploit' => self }
    )

    dport = s.getsockname[2]

    @state[c][:passive_sock] = s
    @state[c][:passive_port] = dport
    add_socket(s)
  end

  @state[c][:passive_port]
end

#setupObject

Prepares the module for exploitation, initializes any state, and starts the payload handler.


30
31
32
33
# File 'lib/msf/core/exploit/ftpserver.rb', line 30

def setup
  super
  @state = {}
end