local coroutine = require "coroutine" local dns = require "dns" local ipOps = require "ipOps" local nmap = require "nmap" local stdnse = require "stdnse" local string = require "string" local tab = require "tab" local table = require "table" description = [[ Performs a quick reverse DNS lookup of an IPv6 network using a technique which analyzes DNS server response codes to dramatically reduce the number of queries needed to enumerate large networks. The technique essentially works by adding an octet to a given IPv6 prefix and resolving it. If the added octet is correct, the server will return NOERROR, if not a NXDOMAIN result is received. The technique is described in detail on Peter's blog: http://7bits.nl/blog/2012/03/26/finding-v6-hosts-by-efficiently-mapping-ip6-arpa ]] --- -- @usage -- nmap --script dns-ip6-arpa-scan --script-args='prefix=2001:0DB8::/48' -- -- @see dns-nsec3-enum.nse -- @see dns-nsec-enum.nse -- @see dns-brute.nse -- @see dns-zone-transfer -- -- @output -- Pre-scan script results: -- | dns-ip6-arpa-scan: -- | ip ptr -- | 2001:0DB8:0:0:0:0:0:2 resolver1.example.com -- |_2001:0DB8:0:0:0:0:0:3 resolver2.example.com -- -- @args prefix the ip6 prefix to scan -- @args mask the ip6 mask to start scanning from author = "Patrik Karlsson" license = "Same as Nmap--See https://nmap.org/book/man-legal.html" categories = {"intrusive", "discovery"} local arg_prefix = stdnse.get_script_args(SCRIPT_NAME .. ".prefix") local arg_mask = stdnse.get_script_args(SCRIPT_NAME .. ".mask") -- Return a prefix and mask based on script arguments. First checks for "/" -- netmask syntax; then looks for a "mask" script argument if that fails. The -- "/" syntax wins over "mask" if both are present. local function get_prefix_mask(arg_prefix, arg_mask) if not arg_prefix then return end local prefix, mask = string.match(arg_prefix, "^(.*)/(.*)$") if not mask then prefix, mask = arg_prefix, arg_mask end return prefix, mask end prerule = function() local prefix, mask = get_prefix_mask(arg_prefix, arg_mask) return prefix and mask end local function query_prefix(query, result) local condvar = nmap.condvar(result) local status, res = dns.query(query, { dtype='PTR' }) if ( not(status) and res == "No Answers") then table.insert(result, query) elseif ( status ) then local ip = query:sub(1, -10):gsub('%.',''):reverse():gsub('(....)', '%1:'):sub(1, -2) ip = ipOps.bin_to_ip(ipOps.ip_to_bin(ip)) table.insert(result, { ptr = res, query = query, ip = ip } ) end condvar "signal" end action = function() local prefix, mask = get_prefix_mask(arg_prefix, arg_mask) local query = dns.reverse(prefix) -- cut the query name down to the length of the prefix local len = (( mask / 8 ) * 4) + #(".ip6.arpa") - 1 local found = { query:sub(-len) } local threads = {} local i = 20 local result repeat result = {} for _, f in ipairs(found) do for q in ("0123456789abcdef"):gmatch("(%w)") do local co = stdnse.new_thread(query_prefix, q .. "." .. f, result) threads[co] = true end end local condvar = nmap.condvar(result) repeat for t in pairs(threads) do if ( coroutine.status(t) == "dead" ) then threads[t] = nil end end if ( next(threads) ) then condvar "wait" end until( next(threads) == nil ) if ( 0 == #result ) then return end found = result i = i + 1 until( 128 == i * 2 + mask ) table.sort(result, function(a,b) return (a.ip < b.ip) end) local output = tab.new(2) tab.addrow(output, "ip", "ptr") for _, item in ipairs(result) do tab.addrow(output, item.ip, item.ptr) end return "\n" .. tab.dump(output) end