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local comm = require "comm"
local datetime = require "datetime"
local os = require "os"
local nmap = require "nmap"
local shortport = require "shortport"
local stdnse = require "stdnse"
local string = require "string"
local table = require "table"
local lpeg = require "lpeg"
local U = require "lpeg-utility"
description = [[
Gets the time and configuration variables from an NTP server. We send two
requests: a time request and a "read variables" (opcode 2) control message.
Without verbosity, the script shows the time and the value of the
<code>version</code>, <code>processor</code>, <code>system</code>,
<code>refid</code>, and <code>stratum</code> variables. With verbosity, all
variables are shown.
See RFC 1035 and the Network Time Protocol Version 4 Reference and
Implementation Guide
(http://www.eecis.udel.edu/~mills/database/reports/ntp4/ntp4.pdf) for
documentation of the protocol.
]]
---
-- @usage
-- nmap -sU -p 123 --script ntp-info <target>
-- @output
-- PORT STATE SERVICE VERSION
-- 123/udp open ntp NTP v4.2.4p4@1.1520-o
-- | ntp-info:
-- | receive time stamp: Sat Dec 12 16:22:41 2009
-- | version: ntpd 4.2.4p4@1.1520-o Wed May 13 21:06:31 UTC 2009 (1)
-- | processor: x86_64
-- | system: Linux/2.6.24-24-server
-- | stratum: 2
-- |_ refid: 195.145.119.188
--
-- @xmloutput
-- <elem key="receive time stamp">2013-10-18T18:03:05</elem>
-- <elem key="version">ntpd 4.2.6p3@1.2290-o Tue Jun 5 20:12:11 UTC 2012 (1)</elem>
-- <elem key="processor">i686</elem>
-- <elem key="system">Linux/3.9.3-24</elem>
-- <elem key="leap">3</elem>
-- <elem key="stratum">16</elem>
-- <elem key="precision">-20</elem>
-- <elem key="rootdelay">0.000</elem>
-- <elem key="rootdisp">2502.720</elem>
-- <elem key="refid">INIT</elem>
-- <elem key="reftime">0x00000000.00000000</elem>
-- <elem key="clock">0xd60bf655.4cc0ba51</elem>
-- <elem key="peer">0</elem>
-- <elem key="tc">3</elem>
-- <elem key="mintc">3</elem>
-- <elem key="offset">0.000</elem>
-- <elem key="frequency">-46.015</elem>
-- <elem key="jitter">0.001</elem>
-- <elem key="wander">0.000</elem>
author = "Richard Sammet"
license = "Same as Nmap--See https://nmap.org/book/man-legal.html"
categories = {"default", "discovery", "safe"}
portrule = shortport.port_or_service(123, "ntp", {"udp", "tcp"})
-- This script run against open|filtered ports, so don't wait too long if
-- there's no response.
local TIMEOUT = 5000
-- Only these fields from the response are displayed with default verbosity.
local DEFAULT_FIELDS = {"version", "processor", "system", "refid", "stratum"}
-- comma-space-separated key=value pairs with optional quotes
local kvmatch = U.localize( {
lpeg.V "space"^0 * lpeg.V "kv" * lpeg.P ","^-1,
kv = lpeg.V "key" * lpeg.P "="^-1 * lpeg.V "value",
key = lpeg.C( (lpeg.V "alnum" + lpeg.S "_-.")^1 ),
value = U.escaped_quote() + lpeg.C((lpeg.P(1) - ",")^0),
} )
action = function(host, port)
local status
local buftres, bufrlres
local output = stdnse.output_table()
-- This is a ntp v2 mode3 (client) date/time request.
local treq = string.char(0xd3, 0x00, 0x04, 0xfa, 0x00, 0x01, 0x00, 0x00,
0x00, 0x01, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0x00)
-- This is a ntp v2 mode6 (control) rl (readlist/READVAR(2)) request. See
-- appendix B of RFC 1305.
local rlreq = string.char(0x16, 0x02, 0x00, 0x01, 0x00, 0x00, 0x00, 0x00,
0x00, 0x00, 0x00, 0x00)
status, buftres = comm.exchange(host, port, treq, {timeout=TIMEOUT})
if status then
local recvtime = os.time()
local sec, frac = string.unpack(">I4I4", buftres, 33)
-- The NTP epoch is 1900-01-01, so subtract 70 years to bring the date into
-- the range Lua expects. The number of seconds at 1970-01-01 is taken from
-- the NTP4 reference above.
local tstamp = sec - 2208988800 + frac / 0x10000000
datetime.record_skew(host, tstamp, recvtime)
output["receive time stamp"] = datetime.format_timestamp(tstamp)
end
status, bufrlres = comm.exchange(host, port, rlreq, {timeout=TIMEOUT})
if status then
-- This only looks at the first fragment of what can possibly be several
-- fragments in the response.
-- Skip the first 10 bytes of the header, then get the data which is
-- preceded by a 2-byte length.
local data = string.unpack(">s2", bufrlres, 11)
-- loop over capture pairs which represent (key, value)
local function accumulate_output (...)
local k, v = ...
if k == nil then return end
output[k] = v
return accumulate_output(select(3, ...))
end
-- do the match and accumulate the captures
local list = kvmatch^0 / accumulate_output
list:match(data)
end
if(#output > 0) then
stdnse.debug1("Test len: %d", #output)
nmap.set_port_state(host, port, "open")
if output['version'] then
-- Look for the version string from the official ntpd and format it
-- in a manner similar to the output of the standard Nmap version detection
local version_num = string.match(output['version'],"^ntpd ([^ ]+)")
if version_num then
port.version.version = "v" .. version_num
nmap.set_port_version(host, port, "hardmatched")
end
end
if output['system'] then
port.version.ostype = output['system']
nmap.set_port_version(host, port, "hardmatched")
end
if nmap.verbosity() < 1 then
local mt = getmetatable(output)
mt["__tostring"] = function(t)
local out = {}
for _,k in ipairs(DEFAULT_FIELDS) do
if output[k] ~= nil then
table.insert(out, ("%s: %s"):format(k, output[k]))
end
end
return "\n " .. table.concat(out, "\n ")
end
end
return output
else
return nil
end
end
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