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: 0.75, 0.9, 0.95, 0.975, 0.99, 0.995, or 0.9995. -- @args delay Average delay between packet sends. This is a number followed by ms for milliseconds or s for seconds. (m and h are also supported but are too long for timeouts.) The actual delay will randomly vary between 50% and 150% of the time specified. Default: 200ms. -- @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 http://nmap.org/book/man-legal.html" categories = {"safe", "discovery"} require 'stdnse' require 'bin' require 'packet' require 'tab' require 'nmap' -- 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) 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.print_verbose("%s not running for lack of privileges.", SCRIPT_NAME) end nmap.registry[SCRIPT_NAME].rootfail = true return nil end local numopen, numclosed = NUMOPEN, NUMCLOSED if nmap.address_family() ~= 'inet' then stdnse.print_debug("%s is IPv4 compatible only.", SCRIPT_NAME) 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 = packet.toip(host.bin_ip_src) local daddr = packet.toip(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)) 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