local ftp = require "ftp"
local nmap = require "nmap"
local shortport = require "shortport"
local stdnse = require "stdnse"
local string = require "string"
local table = require "table"
description = [[
Checks if an FTP server allows anonymous logins.
If anonymous is allowed, gets a directory listing of the root directory
and highlights writeable files.
]]
---
-- @args ftp-anon.maxlist The maximum number of files to return in the
-- directory listing. By default it is 20, or unlimited if verbosity is
-- enabled. Use a negative number to disable the limit, or
-- <code>0</code> to disable the listing entirely.
--
-- @output
-- PORT STATE SERVICE
-- 21/tcp open ftp
-- | ftp-anon: Anonymous FTP login allowed (FTP code 230)
-- | -rw-r--r-- 1 1170 924 31 Mar 28 2001 .banner
-- | d--x--x--x 2 root root 1024 Jan 14 2002 bin
-- | d--x--x--x 2 root root 1024 Aug 10 1999 etc
-- | drwxr-srwt 2 1170 924 2048 Jul 19 18:48 incoming [NSE: writeable]
-- | d--x--x--x 2 root root 1024 Jan 14 2002 lib
-- | drwxr-sr-x 2 1170 924 1024 Aug 5 2004 pub
-- |_Only 6 shown. Use --script-args ftp-anon.maxlist=-1 to see all.
author = "Eddie Bell, Rob Nicholls, Ange Gutek, David Fifield"
license = "Same as Nmap--See http://nmap.org/book/man-legal.html"
categories = {"default", "auth", "safe"}
portrule = shortport.port_or_service(21, "ftp")
-- ---------------------
-- Directory listing function.
-- We ask for a PASV connexion, catch the port returned by the server, send a
-- LIST on the commands socket, connect to the data one and read the directory
-- list sent.
-- ---------------------
local function list(socket, target, max_lines)
local status, err
-- ask the server for a Passive Mode: it should give us a port to
-- listen to, where it will dump the directory listing
local buffer = stdnse.make_buffer(socket, "\r?\n")
status, err = socket:send("PASV\r\n")
if not status then
return status, err
end
local code, message = ftp.read_reply(buffer)
-- Compute the PASV port as given by the server
-- The server should answer with something like
-- 2xx Entering Passive Mode (a,b,c,d,hp,lp)
-- (-- IP--,PORT)
-- PORT is (hp x 256) + lp
local high, low = string.match(message, "%(%d+,%d+,%d+,%d+,(%d+),(%d+)%)")
if not high then
return nil, string.format("Can't parse PASV response: %q", message)
end
local pasv_port = high * 256 + low
-- Send the LIST command on the commands socket. "Fire and forget"; we
-- don't need to take care of the answer on this socket.
status, err = socket:send("LIST\r\n")
if not status then
return status, err
end
local list_socket = nmap.new_socket()
status, err = list_socket:connect(target, pasv_port, "tcp")
if not status then
return status, err
end
local listing = {}
while not max_lines or #listing < max_lines do
local status, data = list_socket:receive_buf("\r?\n", false)
if (not status and data == "EOF") or data == "" then
break
end
if not status then
return status, data
end
listing[#listing + 1] = data
end
return true, listing
end
--- Connects to the FTP server and checks if the server allows anonymous logins.
action = function(host, port)
local socket = nmap.new_socket()
local code, message
local err_catch = function()
socket:close()
end
local max_list = stdnse.get_script_args("ftp-anon.maxlist")
if not max_list then
if nmap.verbosity() == 0 then
max_list = 20
else
max_list = nil
end
else
max_list = tonumber(max_list)
if max_list < 0 then
max_list = nil
end
end
local try = nmap.new_try(err_catch)
try(socket:connect(host, port))
local buffer = stdnse.make_buffer(socket, "\r?\n")
-- Read banner.
code, message = ftp.read_reply(buffer)
if code and code == 220 then
try(socket:send("USER anonymous\r\n"))
code, message = ftp.read_reply(buffer)
if code == 331 then
-- 331: User name okay, need password.
try(socket:send("PASS IEUser@\r\n"))
code, message = ftp.read_reply(buffer)
end
if code == 332 then
-- 332: Need account for login.
-- This is rarely seen but may come in response to a
-- USER or PASS command. As we're doing this
-- anonymously, send back a blank ACCT.
try(socket:send("ACCT\r\n"))
code, message = ftp.read_reply(buffer)
if code == 331 then
-- 331: User name okay, need password.
try(socket:send("PASS IEUser@\r\n"))
code, message = ftp.read_reply(buffer)
end
end
end
if code and code >= 200 and code < 300 then
-- We are primarily looking for 230: User logged in, proceed.
else
if not code then
stdnse.print_debug(1, "ftp-anon: got socket error %q.", message)
elseif code == 421 or code == 530 then
-- Don't log known error codes.
-- 421: Service not available, closing control connection.
-- 530: Not logged in.
else
stdnse.print_debug(1, "ftp-anon: got code %d %q.", code, message)
end
return nil
end
local result = {}
result[#result + 1] = "Anonymous FTP login allowed (FTP code " .. code .. ")"
if not max_list or max_list > 0 then
local status, listing = list(socket, host, max_list)
socket:close()
if not status then
result[#result + 1] = "Can't get directory listing: " .. listing
else
for _, item in ipairs(listing) do
-- Just a quick passive check on user rights.
if string.match(item, "^[d-].......w.") then
item = item .. " [NSE: writeable]"
end
result[#result + 1] = item
end
if max_list and #listing == max_list then
result[#result + 1] = string.format("Only %d shown. Use --script-args %s.maxlist=-1 to see all.", #listing, SCRIPT_NAME)
end
end
end
return table.concat(result, "\n")
end
@KyuuKazami