--- The following file contains a list of decoders used by the
-- broadcast-listener script. A decoder can be either "ethernet" based or IP
-- based. As we're only monitoring broadcast traffic (ie. traffic not
-- explicitly addressed to us) we're mainly dealing with:
-- o UDP broadcast or multicast traffic
-- o ethernet broadcast traffic
--
-- Hence, the Decoder table defines two sub tables ether and udp.
-- In order to match an incoming UDP packet the destination port number is
-- used, therefore each function is indexed based on their destination port
-- for the udp based decoders. For the ether table each decoder function is
-- indexed according to a pattern that the decoding engine attempts to match.
--
-- Each decoder defines three functions:
-- o <code>new</code> - creates a new instance of the decoder
-- o <code>process</code> - process a packet passed through the
-- <code>data</code> argument.
-- o <code>getResults</code> - retrieve any discovered results
--
-- The discovery engine creates an instance of each decoder once it's needed.
-- Then discovery engine stores this instance in a decoder table for reference
-- once the next packet of the same type comes in. This allows the engine to
-- discard duplicate packets and to request the collected results at the end
-- of the session.
--
-- Currently, the packet decoder decodes the following protocols:
-- o Ether
-- x ARP requests (IPv4)
-- x CDP - Cisco Discovery Protocol
-- x EIGRP - Cisco Enhanced Interior Gateway Routing Protocol
--
-- o UDP
-- x DHCP
-- x Netbios
-- x SSDP
-- x HSRP
-- x DropBox
-- x Logitech SqueezeBox Discovery
-- x Multicast DNS/Bonjour/ZeroConf
-- x Spotify
--
--
-- @author "Patrik Karlsson <patrik@cqure.net>"
-- @copyright Same as Nmap--See http://nmap.org/book/man-legal.html
-- Version 0.2
-- Created 07/25/2011 - v0.1 - created by Patrik Karlsson
-- 02/12/2012 - v.02 - added support for EIGRP - Tom Sellers
require 'target'
Decoders = {
ether = {
-- ARP IPv4
['^00..08000604'] = {
new = function(self)
local o = { dups = {} }
setmetatable(o, self)
self.__index = self
return o
end,
process = function(self, data)
local ipOps = require("ipOps")
local pos, hw, proto, hwsize, protosize, opcode = bin.unpack(">SSCCS", data)
-- this shouldn't ever happen, given our filter
if ( hwsize ~= 6 ) then return end
local sender, target = {}, {}
-- if this isn't an ARP request, abort
if ( opcode ~= 1 ) then return end
pos, sender.mac,
sender.ip,
target.mac,
target.ip = bin.unpack("<H" .. hwsize .. "IH" .. hwsize .. "I", data, pos)
if ( not(self.results) ) then
self.results = tab.new(3)
tab.addrow(self.results, 'sender ip', 'sender mac', 'target ip')
end
if ( not(self.dups[("%d:%s"):format(sender.ip,sender.mac)]) ) then
if ( target.ALLOW_NEW_TARGETS ) then target.add(sender.ip) end
local mac = sender.mac:gsub("(..)(..)(..)(..)(..)(..)","%1:%2:%3:%4:%5:%6")
self.dups[("%d:%s"):format(sender.ip,sender.mac)] = true
tab.addrow(self.results, ipOps.fromdword(sender.ip), mac, ipOps.fromdword(target.ip))
end
end,
getResults = function(self) return { name = "ARP Request", (self.results and tab.dump(self.results) or "") } end,
},
-- CDP
['^AAAA..00000C2000'] = {
new = function(self)
local o = { dups = {} }
setmetatable(o, self)
self.__index = self
return o
end,
getAddresses = function(data)
local ipOps = require("ipOps")
local pos, proto_type, proto_len, addr_proto, addr_len, dev_addr, count
local addr_list = ''
pos, count = bin.unpack(">I", data)
for i=1, count do
pos, proto_type, proto_len = bin.unpack(">CC", data, pos)
pos, addr_proto = bin.unpack(">H" .. proto_len, data, pos)
if ( addr_proto == 'CC' ) then
-- IPv4 address, extract it
pos, addr_len = bin.unpack(">S", data, pos)
pos, dev_addr = bin.unpack("<I", data, pos)
addr_list = addr_list .. ' ' .. ipOps.fromdword(dev_addr)
end
-- Add code here for IPv6, others
end
return addr_list
end,
process = function(self, data)
local pos, ver, ttl, chk = bin.unpack(">CCS", data, 9)
if ( ver ~= 2 ) then return end
if ( not(self.results) ) then
self.results = tab.new(5)
tab.addrow( self.results, 'ip', 'id', 'platform', 'version', 'notes' )
end
local result_part = {}
result_part.notes = ''
while ( pos < #data ) do
local typ, len, typdata
pos, typ, len = bin.unpack(">SS", data, pos)
pos, typdata = bin.unpack("A" .. len - 4, data, pos)
-- Device ID
if ( typ == 1 ) then
result_part.id = typdata
-- Version
elseif ( typ == 5 ) then
result_part.version = typdata:match(", Version (.-),")
-- Platform
elseif ( typ == 6 ) then
result_part.platform = typdata
-- Address
elseif ( typ == 2 ) then
result_part.ip = self.getAddresses(typdata)
elseif ( typ == 10) then
local _, mgmt_vlan = bin.unpack(">S", data,pos - 2)
result_part.notes = result_part.notes .. 'native vlan:' .. mgmt_vlan .. ' '
-- Management Address
elseif ( typ == 22 ) then
result_part.notes = result_part.notes .. 'mgmt ip:' .. self.getAddresses(typdata) .. ' '
-- TODO: add more decoding of types here ...
end
end
-- TODO: add code for dups check
if ( not(self.dups[result_part.ip]) ) then
self.dups[result_part.ip] = true
tab.addrow( self.results, result_part.ip, result_part.id, result_part.platform, result_part.version, result_part.notes )
end
end,
getResults = function(self) return { name = "CDP", (self.results and tab.dump(self.results) or "") } end,
},
-- EIGRP Query & Update
['020[13]....00000000'] = {
new = function(self)
local o = { dups = {} }
setmetatable(o, self)
self.__index = self
return o
end,
process = function(self, layer3)
local p = packet.Packet:new( layer3, #layer3 )
-- EIGRP is IP protocol 88 (0x58), so verify this
if ( p.ip_p ~= 88 ) then return end
local data = layer3:sub(p.ip_data_offset + 1)
-- Extract the EIGRP header
local pos, ver, opcode, checksum, flags, seq, ack, asnum = bin.unpack(">CCSiiii", data)
local route_type, size, nexthop, delay, bandwidth, temp, mtu, orig_router, orig_as, arbtag
local hop_count, reliability, load, reserved, mask
local destination
-- Iterate over the routes
while ( pos < #data ) do
-- Get the route type as the packet construction varies
pos,route_type = bin.unpack(">S", data, pos)
if ( route_type == 258 ) then
route_type = 'internal'
pos, size, nexthop, delay, bandwidth, temp, mtu = bin.unpack(">SiiiCS", data, pos)
pos, hop_count, reliability, load, reserved, mask = bin.unpack(">CCCSC", data, pos)
local oct1, oct2, oct3, oct4 = 0, 0, 0, 0
-- unneeded address octets are left out of the packets, lets fill in the gaps
if ( size == 29 ) then
-- mask 25 or above
pos, oct1, oct2, oct3, oct4 = bin.unpack(">CCCC", data, pos)
elseif ( size == 28 ) then
pos, oct1, oct2, oct3 = bin.unpack(">CCC", data, pos)
elseif ( size == 27 ) then
pos, oct1, oct2 = bin.unpack(">CC", data, pos)
elseif ( size == 26 ) then
pos, oct1 = bin.unpack(">C", data, pos)
end
destination = oct1 .. '.' .. oct2 .. '.' .. oct3 .. '.' .. oct4 .. "/" .. mask
orig_router = 'n/a'
elseif ( route_type == 259 ) then
-- external route, from a different routing protocol
pos, size, nexthop = bin.unpack(">Si", data, pos)
local orig_rtr_oct1, orig_rtr_oct2, orig_rtr_oct3, orig_rtr_oct4
pos, orig_rtr_oct1, orig_rtr_oct2, orig_rtr_oct3, orig_rtr_oct4 = bin.unpack(">CCCC", data, pos)
orig_router = orig_rtr_oct1 .. '.' .. orig_rtr_oct2 .. '.' .. orig_rtr_oct3 .. '.' .. orig_rtr_oct4
pos, orig_as, arbtag, ext_metric = bin.unpack(">iii", data, pos)
pos, reserved, ext_proto_id, flags, delay, bandwidth = bin.unpack(">SCCii", data, pos)
pos, temp, mtu, hop_count, reliability, load, reserved, mask = bin.unpack(">CSCCCSC", data, pos)
local oct1, oct2, oct3, oct4 = 0, 0, 0, 0
-- unneeded address octets are left out of the packets, lets fill in the gaps
if ( size == 49 ) then
-- mask 25 or above
pos, oct1, oct2, oct3, oct4 = bin.unpack(">CCCC", data, pos)
elseif ( size == 48 ) then
pos, oct1, oct2, oct3 = bin.unpack(">CCC", data, pos)
elseif ( size == 47 ) then
pos, oct1, oct2 = bin.unpack(">CC", data, pos)
elseif ( size == 46 ) then
pos, oct1 = bin.unpack(">C", data, pos)
end
destination = oct1 .. '.' .. oct2 .. '.' .. oct3 .. '.' .. oct4 .. "/" .. mask
local Proto_Types = {
[1] = 'external (IGRP)',
[2] = 'external (EIGRP)',
[3] = 'external (static)',
[4] = 'external (RIP)',
[6] = 'external (OSPF)',
[9] = 'external (RIP)'
}
route_type = Proto_Types[ext_proto_id]
end
if ( not(self.results) ) then
self.results = tab.new(9)
tab.addrow(self.results, 'sender ip', 'AS#', 'route type', 'destination', 'hop', 'bandwidth', 'delay', 'seq','orig router')
end
if (delay == -1) then delay = 'unreachable' end
if ( not(self.dups[("%s:%s:s:%s"):format(p.ip_src,asnum,destination,seq)]) ) then
if ( target.ALLOW_NEW_TARGETS ) then target.add(p.ip_src) end
self.dups[("%s:%s:%s:%s"):format(p.ip_src,asnum,destination,seq)] = true
tab.addrow( self.results, p.ip_src, asnum, route_type, destination, hop_count, bandwidth, delay, seq, orig_router )
end
end
end,
getResults = function(self) return { name = "EIGRP Query", (self.results and tab.dump(self.results) or "") } end,
},
['0205....00000000'] = {
new = function(self)
local o = { dups = {} }
setmetatable(o, self)
self.__index = self
return o
end,
process = function(self, layer3)
local p = packet.Packet:new( layer3, #layer3 )
-- EIGRP is IP protocol 88 (0x58), so verify this
if ( p.ip_p ~= 88 ) then return end
local data = layer3:sub(p.ip_data_offset + 1)
-- Extract the EIGRP header
local pos, ver, opcode, checksum, flags, seq, ack, asnum = bin.unpack(">CCSiiii", data)
-- Skip the parameters for now.
pos = pos + 10
local holdtime, software, size, ios_major, ios_minor, eigrp_major, eigrp_minor
pos, holdtime, software, size, ios_major, ios_minor, eigrp_major, eigrp_minor = bin.unpack(">SSSCCCC", data, pos)
if ( not(self.results) ) then
self.results = tab.new(5)
tab.addrow(self.results, 'sender ip', 'AS number', 'hold time', 'EIGRP version', 'IOS version')
end
if ( not(self.dups[("%s:%s"):format(p.ip_src,asnum)]) ) then
if ( target.ALLOW_NEW_TARGETS ) then target.add(p.ip_src) end
self.dups[("%s:%s"):format(p.ip_src,asnum)] = true
tab.addrow( self.results, p.ip_src, asnum, holdtime, eigrp_major .. '.' .. eigrp_minor, ios_major .. '.' .. ios_minor )
end
end,
getResults = function(self) return { name = "EIGRP Hello", (self.results and tab.dump(self.results) or "") } end,
},
},
udp = {
-- DHCP
[68] = {
new = function(self)
local o = { dups = {} }
setmetatable(o, self)
self.__index = self
return o
end,
getOption = function(options, name)
for _, v in ipairs(options) do
if ( v.name == name ) then
if ( type(v.value) == "table" ) then
return stdnse.strjoin(", ", v.value)
else
return v.value
end
end
end
end,
process = function(self, layer3)
local dhcp = require("dhcp")
local p = packet.Packet:new( layer3, #layer3 )
local data = layer3:sub(p.udp_offset + 9)
-- the dhcp.parse function isn't optimal for doing
-- this, but it will do for now. First, we need to
-- extract the xid as the parse function checks that it
-- was the same as in the request, which we didn't do.
local pos, msgtype, _, _, _, xid = bin.unpack("<CCCCA4", data)
-- attempt to parse the data
local status, result = dhcp.dhcp_parse(data, xid)
if ( status ) then
if ( not(self.results) ) then
self.results = tab.new(5)
tab.addrow(self.results, "srv ip", "cli ip", "mask", "gw", "dns" )
end
local uniq_key = ("%s:%s"):format(p.ip_src, result.yiaddr_str)
if ( not(self.dups[uniq_key]) ) then
if ( target.ALLOW_NEW_TARGETS ) then target.add(p.ip_src) end
local mask = self.getOption(result.options, "Subnet Mask") or "-"
local gw = self.getOption(result.options, "Router") or "-"
local dns = self.getOption(result.options, "Domain Name Server") or "-"
tab.addrow(self.results, p.ip_src, result.yiaddr_str, mask, gw, dns )
end
end
end,
getResults = function(self) return { name = "DHCP", (self.results and tab.dump(self.results) or "") } end,
},
-- Netbios
[137] = {
new = function(self)
local o = { dups = {} }
setmetatable(o, self)
self.__index = self
return o
end,
process = function(self, layer3)
local dns = require('dns')
local bin = require('bin')
local netbios = require('netbios')
local p = packet.Packet:new( layer3, #layer3 )
local data = layer3:sub(p.udp_offset + 9)
local dresp = dns.decode(data)
if ( not(dresp.questions) or #dresp.questions < 1 ) then return end
local name = netbios.name_decode("\32" .. dresp.questions[1].dname)
if ( not(self.results) ) then
self.results = tab.new(2)
tab.addrow( self.results, 'ip', 'query' )
end
-- check for duplicates
if ( not(self.dups[("%s:%s"):format(p.ip_src, name)]) ) then
if ( target.ALLOW_NEW_TARGETS ) then target.add(p.ip_src) end
tab.addrow( self.results, p.ip_src, name )
self.dups[("%s:%s"):format(p.ip_src, name)] = true
end
end,
getResults = function(self) return { name = "Netbios", (self.results and tab.dump(self.results) or "") } end,
},
--- SSDP
[1900] = {
new = function(self)
local o = { dups = {} }
setmetatable(o, self)
self.__index = self
return o
end,
process = function(self, layer3)
local p = packet.Packet:new( layer3, #layer3 )
local data = layer3:sub(p.udp_offset + 9)
local headers = stdnse.strsplit("\r\n", data)
for _, h in ipairs(headers) do
local st = ""
if ( h:match("^ST:.*") ) then
st = h:match("^ST:(.*)")
if ( not(self.results) ) then
self.results = tab.new(1)
tab.addrow( self.results, 'ip', 'uri' )
end
if ( not(self.dups[("%s:%s"):format(p.ip_src,st)]) ) then
if ( target.ALLOW_NEW_TARGETS ) then target.add(p.ip_src) end
tab.addrow( self.results, p.ip_src, st )
self.dups[("%s:%s"):format(p.ip_src,st)] = true
end
end
end
end,
getResults = function(self) return { name = "SSDP", (self.results and tab.dump(self.results) or "") } end,
},
--- HSRP
[1985] = {
new = function(self)
local o = { dups = {} }
setmetatable(o, self)
self.__index = self
return o
end,
process = function(self, layer3)
local p = packet.Packet:new( layer3, #layer3 )
local data = layer3:sub(p.udp_offset + 9)
local ipOps = require("ipOps")
local State = {
[0] = "Initial",
[1] = "Learn",
[2] = "Listen",
[4] = "Speak",
[8] = "Standby",
[16] = "Active"
}
local Op = {
[0] = "Hello",
[1] = "Coup",
[2] = "Resign",
}
local pos, version, op, state, _, _, prio, group, _, secret = bin.unpack("CCCCCCCCz", data)
if ( version ~= 0 ) then return end
pos = pos + ( 7 - #secret )
local virtip
pos, virtip = bin.unpack("<I", data, pos)
if ( not(self.dups[p.ip_src]) ) then
if ( not(self.results) ) then
self.results = tab.new(7)
tab.addrow(self.results, 'ip', 'version', 'op', 'state', 'prio', 'group', 'secret', 'virtual ip')
end
if ( target.ALLOW_NEW_TARGETS ) then target.add(p.ip_src) end
self.dups[p.ip_src] = true
tab.addrow(self.results, p.ip_src, version, Op[op], State[state], prio, group, secret, ipOps.fromdword(virtip))
end
end,
getResults = function(self) return { name = "HSRP", (self.results and tab.dump(self.results) or "") } end,
},
-- Dropbox
[17500] = {
new = function(self)
local o = { dups = {} }
setmetatable(o, self)
self.__index = self
return o
end,
process = function(self, layer3)
local json = require("json")
local p = packet.Packet:new( layer3, #layer3 )
local data = layer3:sub(p.udp_offset + 9)
local status, info = json.parse(data)
if ( not(status) ) then
return false, "Failed to parse JSON data"
end
-- Add host to list.
for _, key1 in pairs({"namespaces", "version"}) do
for key2, val in pairs(info[key1]) do
info[key1][key2] = tostring(info[key1][key2])
end
end
if ( not(self.results) ) then
self.results = tab.new(6)
tab.addrow(
self.results,
'displayname',
'ip',
'port',
'version',
'host_int',
'namespaces'
)
end
if ( not(self.dups[p.ip_src]) ) then
tab.addrow(
self.results,
info.displayname,
p.ip_src,
info.port,
stdnse.strjoin(".", info.version),
info.host_int,
stdnse.strjoin(", ", info.namespaces)
)
self.dups[p.ip_src] = true
if ( target.ALLOW_NEW_TARGETS ) then target.add(p.ip_src) end
end
end,
getResults = function(self) return { name = "DropBox", (self.results and tab.dump(self.results) or "") } end,
},
--- Squeezebox Discovery
[3483] = {
new = function(self)
local o = { dups = {} }
setmetatable(o, self)
self.__index = self
return o
end,
process = function(self, layer3)
local p = packet.Packet:new( layer3, #layer3 )
local data = layer3:sub(p.udp_offset + 9)
if ( data:match("^eIPAD") ) then
if ( not(self.results) ) then
self.results = tab.new(1)
tab.addrow( self.results, 'ip' )
end
if ( not(self.dups[p.ip_src]) ) then
tab.addrow( self.results, p.ip_src )
self.dups[p.ip_src] = true
if ( target.ALLOW_NEW_TARGETS ) then target.add(p.ip_src) end
end
end
end,
getResults = function(self) return { name = "Squeezebox Discovery", (self.results and tab.dump(self.results) or "") } end,
},
-- Multicast DNS/BonJour/ZeroConf
[5353] = {
new = function(self)
local o = { dups = {} }
setmetatable(o, self)
self.__index = self
return o
end,
process = function(self, layer3)
local dns = require('dns')
local bin = require('bin')
local p = packet.Packet:new( layer3, #layer3 )
local data = layer3:sub(p.udp_offset + 9)
local dresp = dns.decode(data)
local name
if ( dresp.questions and #dresp.questions > 0 ) then
name = dresp.questions[1].dname
elseif ( dresp.answers and #dresp.answers > 0 ) then
name = dresp.answers[1].dname
end
if ( not(name) ) then return end
if ( not(self.results) ) then
self.results = tab.new(2)
tab.addrow( self.results, 'ip', 'query' )
end
-- check for duplicates
if ( not(self.dups[("%s:%s"):format(p.ip_src, name)]) ) then
tab.addrow( self.results, p.ip_src, name )
self.dups[("%s:%s"):format(p.ip_src, name)] = true
if ( target.ALLOW_NEW_TARGETS ) then target.add(p.ip_src) end
end
end,
getResults = function(self) return { name = "MDNS", (self.results and tab.dump(self.results) or "") } end,
},
--- Spotify
[57621] = {
new = function(self)
local o = { dups = {} }
setmetatable(o, self)
self.__index = self
return o
end,
process = function(self, layer3)
local p = packet.Packet:new( layer3, #layer3 )
local data = layer3:sub(p.udp_offset + 9)
if ( data:match("^SpotUdp") ) then
if ( not(self.results) ) then
self.results = tab.new(1)
tab.addrow( self.results, 'ip' )
end
if ( not(self.dups[p.ip_src]) ) then
tab.addrow( self.results, p.ip_src )
self.dups[p.ip_src] = true
if ( target.ALLOW_NEW_TARGETS ) then target.add(p.ip_src) end
end
end
end,
getResults = function(self) return { name = "Spotify", (self.results and tab.dump(self.results) or "") } end,
}
}
}