local nmap = require "nmap" local packet = require "packet" local ipOps = require "ipOps" local bin = require "bin" local stdnse = require "stdnse" local table = require "table" local math = require "math" local string = require "string" description = [[ Queries for the multicast path from a source to a destination host. This works by sending an IGMP Traceroute Query and listening for IGMP Traceroute responses. The Traceroute Query is sent to the first hop and contains information about source, destination and multicast group addresses. First hop defaults to the multicast All routers address. The default multicast group address is 0.0.0.0 and the default destination is our own host address. A source address must be provided. The responses are parsed to get interesting information about interface addresses, used protocols and error codes. This is similar to the mtrace utility provided in Cisco IOS. ]] --- --@args mtrace.fromip Source address from which to traceroute. -- --@args mtrace.toip Destination address to which to traceroute. -- Defaults to our host address. -- --@args mtrace.group Multicast group address for the traceroute. -- Defaults to 0.0.0.0 which represents all group addresses. -- --@args mtrace.firsthop Host to which the query is sent. If not set, the -- query will be sent to 224.0.0.2. -- --@args mtrace.timeout Time to wait for responses. -- Defaults to 7s. -- --@usage -- nmap --script mtrace --script-args 'mtrace.fromip=172.16.45.4' -- --@output -- Pre-scan script results: -- | mtrace: -- | Group 0.0.0.0 from 172.16.45.4 to 172.16.0.1 -- | Source: 172.16.45.4 -- | In address: 172.16.34.3 -- | Out address: 172.16.0.3 -- | Protocol: PIM -- | In address: 172.16.45.4 -- | Out address: 172.16.34.4 -- | Protocol: PIM -- | Source: 172.16.45.4 -- | In address: 172.16.13.1 -- | Out address: 172.16.0.2 -- | Protocol: PIM / Static -- | In address: 172.16.34.3 -- | Out address: 172.16.13.3 -- | Protocol: PIM -- | In address: 172.16.45.4 -- | Out address: 172.16.34.4 -- |_ Protocol: PIM author = "Hani Benhabiles" license = "Same as Nmap--See http://nmap.org/book/man-legal.html" categories = {"discovery", "safe", "broadcast"} -- From: https://tools.ietf.org/id/draft-ietf-idmr-traceroute-ipm-07.txt PROTO = { [0x01] = "DVMRP", [0x02] = "MOSPF", [0x03] = "PIM", [0x04] = "CBT", [0x05] = "PIM / Special table", [0x06] = "PIM / Static", [0x07] = "DVMRP / Static", [0x08] = "PIM / MBGP", [0x09] = "CBT / Special table", [0x10] = "CBT / Static", [0x11] = "PIM / state created by Assert processing", } FWD_CODE = { [0x00] = "NO_ERROR", [0x01] = "WRONG_IF", [0x02] = "PRUNE_SENT", [0x03] = "PRUNE_RCVD", [0x04] = "SCOPED", [0x05] = "NO_ROUTE", [0x06] = "WRONG_LAST_HOP", [0x07] = "NOT_FORWARDING", [0x08] = "REACHED_RP", [0x09] = "RPF_IF", [0x0A] = "NO_MULTICAST", [0x0B] = "INFO_HIDDEN", [0x81] = "NO_SPACE", [0x82] = "OLD_ROUTER", [0x83] = "ADMIN_PROHIB", } prerule = function() if nmap.address_family() ~= 'inet' then stdnse.verbose1("is IPv4 only.") return false end if not nmap.is_privileged() then stdnse.verbose1("not running for lack of privileges.") return false end return true end --- Generates a raw IGMP Traceroute Query. --@param fromip Source address. --@param toip Destination address. --@param group Multicast group address. --@param receiver Receiver of the response. --@return data Raw Traceroute Query. local traceRaw = function(fromip, toip, group, receiver) local data = bin.pack(">CCSIIIICCS", 0x1f, -- Type: Traceroute Query 0x20, -- Hops: 32 0x0000, -- Checksum: To be set later ipOps.todword(group), -- Multicast group ipOps.todword(fromip), -- Source ipOps.todword(toip), -- Destination ipOps.todword(receiver), -- Receiver 0x40, -- TTL 0x00, math.random(123456) -- Query ID ) -- We calculate checksum data = data:sub(1,2) .. bin.pack(">S", packet.in_cksum(data)) .. data:sub(5) return data end --- Sends a raw IGMP Traceroute Query. --@param interface Network interface to send through. --@param destination Target host to which the packet is sent. --@param trace_raw Traceroute raw Query. local traceSend = function(interface, destination, trace_raw) local ip_raw = bin.pack("H", "45c00040ed780000400218bc0a00c8750a00c86b") .. trace_raw local trace_packet = packet.Packet:new(ip_raw, ip_raw:len()) trace_packet:ip_set_bin_src(ipOps.ip_to_str(interface.address)) trace_packet:ip_set_bin_dst(ipOps.ip_to_str(destination)) trace_packet:ip_set_len(#trace_packet.buf) trace_packet:ip_count_checksum() if destination == "224.0.0.2" then -- Doesn't affect results as it is ignored but most routers, but RFC -- 3171 should be respected. trace_packet:ip_set_ttl(1) end trace_packet:ip_count_checksum() local sock = nmap.new_dnet() if destination == "224.0.0.2" then sock:ethernet_open(interface.device) -- Ethernet IPv4 multicast, our ethernet address and packet type IP local eth_hdr = bin.pack("HAH", "01 00 5e 00 00 02", interface.mac, "08 00") sock:ethernet_send(eth_hdr .. trace_packet.buf) sock:ethernet_close() else sock:ip_open() sock:ip_send(trace_packet.buf, destination) sock:ip_close() end end --- Parses an IGMP Traceroute Response and returns it in structured form. --@param data Raw Traceroute Response. --@return response Structured Traceroute Response. local traceParse = function(data) local index local response = {} -- first byte should be IGMP type == 0x1e (Traceroute Response) if data:byte(1) ~= 0x1e then return end -- Hops index, response.hops = bin.unpack(">C", data, 2) -- Checksum index, response.checksum = bin.unpack(">S", data, index) -- Group index, response.group = bin.unpack("C", data, index) -- Query ID index, response.qid = bin.unpack(">C", data, index) index, response.qid = response.qid * 2^16 + bin.unpack(">S", data, index) local block response.blocks = {} -- Now, parse data blocks while true do -- To end parsing and not get stuck in infinite loops. if index >= #data then break elseif #data - index < 31 then stdnse.verbose1("malformed traceroute response.") return end block = {} -- Query Arrival index, block.query = bin.unpack(">I", data, index) -- In itf address index, block.inaddr = bin.unpack("I", data, index) -- Out packets index, block.outpkts = bin.unpack(">I", data, index) -- S,G pkt count index, block.sgpkt = bin.unpack(">I", data, index) -- Protocol index, block.proto = bin.unpack(">C", data, index) -- Forward TTL index, block.fwdttl = bin.unpack(">C", data, index) -- Options index, block.options = bin.unpack(">C", data, index) -- Forwarding Code index, block.code = bin.unpack(">C", data, index) table.insert(response.blocks, block) end return response end -- Listens for IGMP Traceroute responses --@param interface Network interface to listen on. --@param timeout Amount of time to listen for in seconds. --@param responses table to insert responses into. local traceListener = function(interface, timeout, responses) local condvar = nmap.condvar(responses) local start = nmap.clock_ms() local listener = nmap.new_socket() local p, trace_raw, status, l3data, response, _ -- IGMP packets that are sent to our host local filter = 'ip proto 2 and dst host ' .. interface.address listener:set_timeout(100) listener:pcap_open(interface.device, 1024, true, filter) while (nmap.clock_ms() - start) < timeout do status, _, _, l3data = listener:pcap_receive() if status then p = packet.Packet:new(l3data, #l3data) trace_raw = string.sub(l3data, p.ip_hl*4 + 1) if p then -- Check that IGMP Type == 0x1e (Traceroute Response) if trace_raw:byte(1) == 0x1e then response = traceParse(trace_raw) if response then response.srcip = p.ip_src table.insert(responses, response) end end end end end condvar("signal") end -- Returns the network interface used to send packets to a target host. --@param target host to which the interface is used. --@return interface Network interface used for target host. local getInterface = function(target) -- First, create dummy UDP connection to get interface local sock = nmap.new_socket() local status, err = sock:connect(target, "12345", "udp") if not status then stdnse.verbose1("%s", err) return end local status, address, _, _, _ = sock:get_info() if not status then stdnse.verbose1("%s", err) return end for _, interface in pairs(nmap.list_interfaces()) do if interface.address == address then return interface end end end action = function() local fromip = stdnse.get_script_args(SCRIPT_NAME .. ".fromip") local toip = stdnse.get_script_args(SCRIPT_NAME .. ".toip") local group = stdnse.get_script_args(SCRIPT_NAME .. ".group") or "0.0.0.0" local firsthop = stdnse.get_script_args(SCRIPT_NAME .. ".firsthop") or "224.0.0.2" local timeout = stdnse.parse_timespec(stdnse.get_script_args(SCRIPT_NAME .. ".timeout")) local responses = {} timeout = (timeout or 7) * 1000 -- Source address from which to traceroute if not fromip then stdnse.verbose1("A source IP must be provided through fromip argument.") return end -- Get network interface to use local interface = nmap.get_interface() if interface then interface = nmap.get_interface_info(interface) else interface = getInterface(firsthop) end if not interface then return stdnse.format_output(false, ("Couldn't get interface for %s"):format(firsthop)) end -- Destination defaults to our own host toip = toip or interface.address stdnse.debug1("Traceroute group %s from %s to %s.", group, fromip, toip) stdnse.debug1("will send to %s via %s interface.", firsthop, interface.shortname) -- Thread that listens for responses stdnse.new_thread(traceListener, interface, timeout, responses) -- Send request after small wait to let Listener start stdnse.sleep(0.1) local trace_raw = traceRaw(fromip, toip, group, interface.address) traceSend(interface, firsthop, trace_raw) local condvar = nmap.condvar(responses) condvar("wait") if #responses > 0 then local outresp local output, outblock = {} table.insert(output, ("Group %s from %s to %s"):format(group, fromip, toip)) for _, response in pairs(responses) do outresp = {} outresp.name = "Source: " .. response.srcip for _, block in pairs(response.blocks) do outblock = {} outblock.name = "In address: " .. block.inaddr table.insert(outblock, "Out address: " .. block.outaddr) -- Protocol if PROTO[block.proto] then table.insert(outblock, "Protocol: " .. PROTO[block.proto]) else table.insert(outblock, "Protocol: Unknown") end -- Error Code, we ignore NO_ERROR which is the normal case. if FWD_CODE[block.code] and block.code ~= 0x00 then table.insert(outblock, "Error code: " .. FWD_CODE[block.code]) elseif block.code ~= 0x00 then table.insert(outblock, "Error code: Unknown") end table.insert(outresp, outblock) end table.insert(output, outresp) end return stdnse.format_output(true, output) end end