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local bin = require "bin"
local ipOps = require "ipOps"
local math = require "math"
local nmap = require "nmap"
local packet = require "packet"
local stdnse = require "stdnse"
local string = require "string"
local tab = require "tab"
local table = require "table"
description = [[
Repeatedly probe open and/or closed ports on a host to obtain a series
of round-trip time values for each port. These values are used to
group collections of ports which are statistically different from other
groups. Ports being in different groups (or "families") may be due to
network mechanisms such as port forwarding to machines behind a NAT.
In order to group these ports into different families, some statistical
values must be computed. Among these values are the mean and standard
deviation of the round-trip times for each port. Once all of the times
have been recorded and these values have been computed, the Student's
t-test is used to test the statistical significance of the differences
between each port's data. Ports which have round-trip times that are
statistically the same are grouped together in the same family.
This script is based on Doug Hoyte's Qscan documentation and patches
for Nmap.
]]
-- See http://hcsw.org/nmap/QSCAN for more on Doug's research
---
-- @usage
-- nmap --script qscan --script-args qscan.confidence=0.95,qscan.delay=200ms,qscan.numtrips=10 target
--
-- @args confidence Confidence level: <code>0.75</code>, <code>0.9</code>,
-- <code>0.95</code>, <code>0.975</code>, <code>0.99</code>,
-- <code>0.995</code>, or <code>0.9995</code>.
-- @args delay Average delay between packet sends. This is a number followed by
-- <code>ms</code> for milliseconds or <code>s</code> for seconds.
-- (<code>m</code> and <code>h</code> are also supported but are too long
-- for timeouts.) The actual delay will randomly vary between 50% and
-- 150% of the time specified. Default: <code>200ms</code>.
-- @args numtrips Number of round-trip times to try to get.
-- @args numopen Maximum number of open ports to probe (default 8). A negative
-- number disables the limit.
-- @args numclosed Maximum number of closed ports to probe (default 1). A
-- negative number disables the limit.
--
-- @output
-- | qscan:
-- | PORT FAMILY MEAN (us) STDDEV LOSS (%)
-- | 21 0 2082.70 460.72 0.0%
-- | 22 0 2211.70 886.69 0.0%
-- | 23 1 4631.90 606.67 0.0%
-- | 24 0 1922.40 336.90 0.0%
-- | 25 0 2017.30 404.31 0.0%
-- | 80 1 4180.80 856.98 0.0%
-- |_443 0 2013.30 368.91 0.0%
--
-- 03/17/2010
author = "Kris Katterjohn"
license = "Same as Nmap--See https://nmap.org/book/man-legal.html"
categories = {"safe", "discovery"}
-- defaults
local DELAY = 0.200
local NUMTRIPS = 10
local CONF = 0.95
local NUMOPEN = 8
local NUMCLOSED = 1
-- The following tdist{} and tinv() are based off of
-- http://www.owlnet.rice.edu/~elec428/projects/tinv.c
local tdist = {
-- 75% 90% 95% 97.5% 99% 99.5% 99.95%
{ 1.0000, 3.0777, 6.3138, 12.7062, 31.8207, 63.6574, 636.6192 }, -- 1
{ 0.8165, 1.8856, 2.9200, 4.3027, 6.9646, 9.9248, 31.5991 }, -- 2
{ 0.7649, 1.6377, 2.3534, 3.1824, 4.5407, 5.8409, 12.9240 }, -- 3
{ 0.7407, 1.5332, 2.1318, 2.7764, 3.7649, 4.6041, 8.6103 }, -- 4
{ 0.7267, 1.4759, 2.0150, 2.5706, 3.3649, 4.0322, 6.8688 }, -- 5
{ 0.7176, 1.4398, 1.9432, 2.4469, 3.1427, 3.7074, 5.9588 }, -- 6
{ 0.7111, 1.4149, 1.8946, 2.3646, 2.9980, 3.4995, 5.4079 }, -- 7
{ 0.7064, 1.3968, 1.8595, 3.3060, 2.8965, 3.3554, 5.0413 }, -- 8
{ 0.7027, 1.3830, 1.8331, 2.2622, 2.8214, 3.2498, 4.7809 }, -- 9
{ 0.6998, 1.3722, 1.8125, 2.2281, 2.7638, 1.1693, 4.5869 }, -- 10
{ 0.6974, 1.3634, 1.7959, 2.2010, 2.7181, 3.1058, 4.4370 }, -- 11
{ 0.6955, 1.3562, 1.7823, 2.1788, 2.6810, 3.0545, 4.3178 }, -- 12
{ 0.6938, 1.3502, 1.7709, 2.1604, 2.6403, 3.0123, 4.2208 }, -- 13
{ 0.6924, 1.3450, 1.7613, 2.1448, 2.6245, 2.9768, 4.1405 }, -- 14
{ 0.6912, 1.3406, 1.7531, 2.1315, 2.6025, 2.9467, 4.0728 }, -- 15
{ 0.6901, 1.3368, 1.7459, 2.1199, 2.5835, 2.9208, 4.0150 }, -- 16
{ 0.6892, 1.3334, 1.7396, 2.1098, 2.5669, 2.8982, 3.9651 }, -- 17
{ 0.6884, 1.3304, 1.7341, 2.1009, 2.5524, 2.8784, 3.9216 }, -- 18
{ 0.6876, 1.3277, 1.7291, 2.0930, 2.5395, 2.8609, 3.8834 }, -- 19
{ 0.6870, 1.3253, 1.7247, 2.0860, 2.5280, 2.8453, 3.8495 }, -- 20
{ 0.6844, 1.3163, 1.7081, 2.0595, 2.4851, 2.7874, 3.7251 }, -- 25
{ 0.6828, 1.3104, 1.6973, 2.0423, 2.4573, 2.7500, 3.6460 }, -- 30
{ 0.6816, 1.3062, 1.6896, 2.0301, 2.4377, 2.7238, 3.5911 }, -- 35
{ 0.6807, 1.3031, 1.6839, 2.0211, 2.4233, 2.7045, 3.5510 }, -- 40
{ 0.6800, 1.3006, 1.6794, 2.0141, 2.4121, 2.6896, 3.5203 }, -- 45
{ 0.6794, 1.2987, 1.6759, 2.0086, 2.4033, 2.6778, 3.4960 }, -- 50
{ 0.6786, 1.2958, 1.6706, 2.0003, 2.3901, 2.6603, 3.4602 }, -- 60
{ 0.6780, 1.2938, 1.6669, 1.9944, 2.3808, 2.6479, 3.4350 }, -- 70
{ 0.6776, 1.2922, 1.6641, 1.9901, 2.3739, 2.6387, 3.4163 }, -- 80
{ 0.6772, 1.2910, 1.6620, 1.9867, 2.3685, 2.6316, 3.4019 }, -- 90
{ 0.6770, 1.2901, 1.6602, 1.9840, 2.3642, 2.6259, 3.3905 } -- 100
}
-- cache ports to probe between the hostrule and the action function
local qscanports
local tinv = function(p, dof)
local din, pin
if dof >= 1 and dof <= 20 then
din = dof
elseif dof < 25 then
din = 20
elseif dof < 30 then
din = 21
elseif dof < 35 then
din = 22
elseif dof < 40 then
din = 23
elseif dof < 45 then
din = 24
elseif dof < 50 then
din = 25
elseif dof < 60 then
din = 26
elseif dof < 70 then
din = 27
elseif dof < 80 then
din = 28
elseif dof < 90 then
din = 29
elseif dof < 100 then
din = 30
elseif dof >= 100 then
din = 31
end
if p == 0.75 then
pin = 1
elseif p == 0.9 then
pin = 2
elseif p == 0.95 then
pin = 3
elseif p == 0.975 then
pin = 4
elseif p == 0.99 then
pin = 5
elseif p == 0.995 then
pin = 6
elseif p == 0.9995 then
pin = 7
end
return tdist[din][pin]
end
--- Calculates intermediate t statistic
local tstat = function(n1, n2, u1, u2, v1, v2)
local dof = n1 + n2 - 2
local a = (n1 + n2) / (n1 * n2)
--local b = ((n1 - 1) * (s1 * s1) + (n2 - 1) * (s2 * s2))
local b = ((n1 - 1) * v1) + ((n2 - 1) * v2)
return math.abs(u1 - u2) / math.sqrt(a * (b / dof))
end
--- Pcap check
-- @return Destination and source IP addresses and TCP ports
local check = function(layer3)
local ip = packet.Packet:new(layer3, layer3:len())
return bin.pack('AA=S=S', ip.ip_bin_dst, ip.ip_bin_src, ip.tcp_dport, ip.tcp_sport)
end
--- Updates a TCP Packet object
-- @param tcp The TCP object
local updatepkt = function(tcp, dport)
tcp:tcp_set_sport(math.random(0x401, 0xffff))
tcp:tcp_set_dport(dport)
tcp:tcp_set_seq(math.random(1, 0x7fffffff))
tcp:tcp_count_checksum(tcp.ip_len)
tcp:ip_count_checksum()
end
--- Create a TCP Packet object
-- @param host Host object
-- @return TCP Packet object
local genericpkt = function(host)
local pkt = bin.pack("H",
"4500 002c 55d1 0000 8006 0000 0000 0000" ..
"0000 0000 0000 0000 0000 0000 0000 0000" ..
"6002 0c00 0000 0000 0204 05b4"
)
local tcp = packet.Packet:new(pkt, pkt:len())
tcp:ip_set_bin_src(host.bin_ip_src)
tcp:ip_set_bin_dst(host.bin_ip)
updatepkt(tcp, 0)
return tcp
end
--- Calculates "family" values for grouping
-- @param stats Statistics table
-- @param conf Confidence level
local calcfamilies = function(stats, conf)
local i, j
local famidx = 0
local stat
local crit
for _, i in pairs(stats) do repeat
if i.fam ~= -1 then
break
end
i.fam = famidx
famidx = famidx + 1
for _, j in pairs(stats) do repeat
if j.port == i.port or j.fam ~= -1 then
break
end
stat = tstat(i.num, j.num, i.mean, j.mean, i.K / (i.num - 1), j.K / (j.num - 1))
crit = tinv(conf, i.num + j.num - 2)
if stat < crit then
j.fam = i.fam
end
until true end
until true end
end
--- Builds report for output
-- @param stats Array of port statistics
-- @return Output report
local report = function(stats)
local j
local outtab = tab.new()
tab.add(outtab, 1, "PORT")
tab.add(outtab, 2, "FAMILY")
tab.add(outtab, 3, "MEAN (us)")
tab.add(outtab, 4, "STDDEV")
tab.add(outtab, 5, "LOSS (%)")
tab.nextrow(outtab)
local port, fam, mean, stddev, loss
for _, j in pairs(stats) do
port = tostring(j.port)
fam = tostring(j.fam)
mean = string.format("%.2f", j.mean)
stddev = string.format("%.2f", math.sqrt(j.K / (j.num - 1)))
loss = string.format("%.1f%%", 100 * (1 - j.num / j.sent))
tab.add(outtab, 1, port)
tab.add(outtab, 2, fam)
tab.add(outtab, 3, mean)
tab.add(outtab, 4, stddev)
tab.add(outtab, 5, loss)
tab.nextrow(outtab)
end
return tab.dump(outtab)
end
--- Returns option values based on script arguments and defaults
-- @return Confidence level, delay and number of trips
local getopts = function()
local conf, delay, numtrips = CONF, DELAY, NUMTRIPS
local bool, err
local k
for _, k in ipairs({"qscan.confidence", "confidence"}) do
if nmap.registry.args[k] then
conf = tonumber(nmap.registry.args[k])
break
end
end
for _, k in ipairs({"qscan.delay", "delay"}) do
if nmap.registry.args[k] then
delay = stdnse.parse_timespec(nmap.registry.args[k])
break
end
end
for _, k in ipairs({"qscan.numtrips", "numtrips"}) do
if nmap.registry.args[k] then
numtrips = tonumber(nmap.registry.args[k])
break
end
end
bool = true
if conf ~= 0.75 and conf ~= 0.9 and
conf ~= 0.95 and conf ~= 0.975 and
conf ~= 0.99 and conf ~= 0.995 and conf ~= 0.9995 then
bool = false
err = "Invalid confidence level"
end
if not delay then
bool = false
err = "Invalid delay"
end
if numtrips < 3 then
bool = false
err = "Invalid number of trips (should be >= 3)"
end
if bool then
return bool, conf, delay, numtrips
else
return bool, err
end
end
local table_extend = function(a, b)
local t = {}
for _, v in ipairs(a) do
t[#t + 1] = v
end
for _, v in ipairs(b) do
t[#t + 1] = v
end
return t
end
--- Get ports to probe
-- @param host Host object
local getports = function(host, numopen, numclosed)
local open = {}
local closed = {}
local port
port = nil
while numopen < 0 or #open < numopen do
port = nmap.get_ports(host, port, "tcp", "open")
if not port then
break
end
open[#open + 1] = port.number
end
port = nil
while numclosed < 0 or #closed < numclosed do
port = nmap.get_ports(host, port, "tcp", "closed")
if not port then
break
end
closed[#closed + 1] = port.number
end
return table_extend(open, closed)
end
hostrule = function(host)
if not nmap.is_privileged() then
nmap.registry[SCRIPT_NAME] = nmap.registry[SCRIPT_NAME] or {}
if not nmap.registry[SCRIPT_NAME].rootfail then
stdnse.verbose1("not running for lack of privileges.")
end
nmap.registry[SCRIPT_NAME].rootfail = true
return nil
end
local numopen, numclosed = NUMOPEN, NUMCLOSED
if nmap.address_family() ~= 'inet' then
stdnse.debug1("is IPv4 compatible only.")
return false
end
if not host.interface then
return false
end
for _, k in ipairs({"qscan.numopen", "numopen"}) do
if nmap.registry.args[k] then
numopen = tonumber(nmap.registry.args[k])
break
end
end
for _, k in ipairs({"qscan.numclosed", "numclosed"}) do
if nmap.registry.args[k] then
numclosed = tonumber(nmap.registry.args[k])
break
end
end
qscanports = getports(host, numopen, numclosed)
return (#qscanports > 1)
end
action = function(host)
local sock = nmap.new_dnet()
local pcap = nmap.new_socket()
local saddr = ipOps.str_to_ip(host.bin_ip_src)
local daddr = ipOps.str_to_ip(host.bin_ip)
local start
local rtt
local stats = {}
local try = nmap.new_try()
local conf, delay, numtrips = try(getopts())
pcap:pcap_open(host.interface, 104, false, "tcp and dst host " .. saddr .. " and src host " .. daddr)
try(sock:ip_open())
try = nmap.new_try(function() sock:ip_close() end)
-- Simply double the calculated host timeout to account for possible
-- extra time due to port forwarding or whathaveyou. Nmap has all
-- ready scanned this host, so the timing should have taken into
-- account some of the RTT differences, but I think it really depends
-- on how many ports were scanned and how many were forwarded where.
-- Play it safer here.
pcap:set_timeout(2 * host.times.timeout * 1000)
local tcp = genericpkt(host)
for i = 1, numtrips do
for j, port in ipairs(qscanports) do
updatepkt(tcp, port)
if not stats[j] then
stats[j] = {}
stats[j].port = port
stats[j].num = 0
stats[j].sent = 0
stats[j].mean = 0
stats[j].K = 0
stats[j].fam = -1
end
start = stdnse.clock_us()
try(sock:ip_send(tcp.buf, host))
stats[j].sent = stats[j].sent + 1
local test = bin.pack('AA=S=S', tcp.ip_bin_src, tcp.ip_bin_dst, tcp.tcp_sport, tcp.tcp_dport)
local status, length, _, layer3, stop = pcap:pcap_receive()
while status and test ~= check(layer3) do
status, length, _, layer3, stop = pcap:pcap_receive()
end
if not stop then
-- probably a timeout, just grab current time
stop = stdnse.clock_us()
else
-- we use usecs
stop = stop * 1000000
end
rtt = stop - start
if status then
-- update more stats on the port, Knuth-style
local delta
stats[j].num = stats[j].num + 1
delta = rtt - stats[j].mean
stats[j].mean = stats[j].mean + delta / stats[j].num
stats[j].K = stats[j].K + delta * (rtt - stats[j].mean)
end
-- Unlike qscan.cc which loops around while waiting for
-- the delay, I just sleep here (depending on rtt)
if rtt < (3 * delay) / 2 then
if rtt < (delay / 2) then
stdnse.sleep(((delay / 2) + math.random(0, delay) - rtt))
else
stdnse.sleep(math.random((3 * delay) / 2 - rtt))
end
end
end
end
sock:ip_close()
pcap:pcap_close()
-- sort by port number
table.sort(stats, function(t1, t2) return t1.port < t2.port end)
calcfamilies(stats, conf)
return "\n" .. report(stats)
end
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