description = [[ Requests a zone transfer (AXFR) from a DNS server. The script sends an AXFR query to a DNS server. The domain to query is determined by examining the name given on the command line, the DNS server's hostname, or it can be specified with the dns-zone-transfer.domain script argument. If the query is successful all domains and domain types are returned along with common type specific data (SOA/MX/NS/PTR/A). This script can run at different phases of an Nmap scan: * Script Pre-scanning: in this phase the script will run before any Nmap scan and use the defined DNS server in the arguments. The script arguments in this phase are: dns-zone-transfer.server the DNS server to use, can be a hostname or an IP address and must be specified. The dns-zone-transfer.port argument is optional and can be used to specify the DNS server port. * Script scanning: in this phase the script will run after the other Nmap phases and against an Nmap discovered DNS server. If we don't have the "true" hostname for the DNS server we cannot determine a likely zone to perform the transfer on. Useful resources * DNS for rocket scientists: http://www.zytrax.com/books/dns/ * How the AXFR protocol works: http://cr.yp.to/djbdns/axfr-notes.html ]] --- -- @args dns-zone-transfer.domain Domain to transfer. -- @args dns-zone-transfer.server DNS server. If set, this argument will -- enable the script for the "Script Pre-scanning phase". -- @args dns-zone-transfer.port DNS server port, this argument concerns -- the "Script Pre-scanning phase" and it's optional, the default -- value is 53. -- @args newtargets If specified, adds returned DNS records onto Nmap -- scanning queue. -- @args dns-zone-transfer.addall If specified, adds all IP addresses -- including private ones onto Nmap scanning queue when the -- script argument newtargets is given. The default -- behavior is to skip private IPs (non-routable). -- @output -- 53/tcp open domain -- | dns-zone-transfer: -- | foo.com. SOA ns2.foo.com. piou.foo.com. -- | foo.com. TXT -- | foo.com. NS ns1.foo.com. -- | foo.com. NS ns2.foo.com. -- | foo.com. NS ns3.foo.com. -- | foo.com. A 127.0.0.1 -- | foo.com. MX mail.foo.com. -- | anansie.foo.com. A 127.0.0.2 -- | dhalgren.foo.com. A 127.0.0.3 -- | drupal.foo.com. CNAME -- | goodman.foo.com. A 127.0.0.4 i -- | goodman.foo.com. MX mail.foo.com. -- | isaac.foo.com. A 127.0.0.5 -- | julie.foo.com. A 127.0.0.6 -- | mail.foo.com. A 127.0.0.7 -- | ns1.foo.com. A 127.0.0.7 -- | ns2.foo.com. A 127.0.0.8 -- | ns3.foo.com. A 127.0.0.9 -- | stubing.foo.com. A 127.0.0.10 -- | vicki.foo.com. A 127.0.0.11 -- | votetrust.foo.com. CNAME -- | www.foo.com. CNAME -- |_ foo.com. SOA ns2.foo.com. piou.foo.com. -- @usage -- nmap --script dns-zone-transfer.nse \ -- --script-args dns-zone-transfer.domain= require('shortport') require('strbuf') require('stdnse') require('listop') require('bit') require('tab') require('dns') require('target') require('ipOps') author = "Eddie Bell" license = "Same as Nmap--See http://nmap.org/book/man-legal.html" categories = {'intrusive', 'discovery'} -- DNS options local dns_opts = {} prerule = function() dns_opts.domain, dns_opts.server, dns_opts.port, dns_opts.addall = stdnse.get_script_args( {"dns-zone-transfer.domain", "dnszonetransfer.domain"}, {"dns-zone-transfer.server", "dnszonetransfer.server"}, {"dns-zone-transfer.port", "dnszonetransfer.port"}, {"dns-zone-transfer.addall","dnszonetransfer.addall"} ) if not dns_opts.domain then stdnse.print_debug(3, "Skipping '%s' %s, 'dnszonetransfer.domain' argument is missing.", SCRIPT_NAME, SCRIPT_TYPE) return false end if not dns_opts.server then stdnse.print_debug(3, "Skipping '%s' %s, 'dnszonetransfer.server' argument is missing.", SCRIPT_NAME, SCRIPT_TYPE) return false end return true end portrule = function(host, port) if shortport.portnumber(53, 'tcp')(host, port) then dns_opts.domain, dns_opts.addall = stdnse.get_script_args( {"dns-zone-transfer.domain", "dnszonetransfer.domain"}, {"dns-zone-transfer.addall","dnszonetransfer.addall"} ) if not dns_opts.domain then if host.targetname then dns_opts.domain = host.targetname elseif host.name ~= "" then dns_opts.domain = host.name else -- can't do anything without a hostname stdnse.print_debug(3, "Skipping '%s' %s, 'dnszonetransfer.domain' argument is missing.", SCRIPT_NAME, SCRIPT_TYPE) return false end end dns_opts.server = host.ip dns_opts.port = port.number return true end return false end --- DNS query and response types. --@class table --@name typetab local typetab = { 'A', 'NS', 'MD', 'MF', 'CNAME', 'SOA', 'MB', 'MG', 'MR', 'NULL', 'WKS', 'PTR', 'HINFO', 'MINFO', 'MX', 'TXT', 'RP', 'AFSDB', 'X25', 'ISDN', 'RT', 'NSAP', 'NSAP-PTR', 'SIG', 'KEY', 'PX', 'GPOS', 'AAAA', 'LOC', 'NXT', 'EID', 'NIMLOC', 'SRV', 'ATMA', 'NAPTR', 'KX', 'CERT', 'A6', 'DNAME', 'SINK', 'OPT', [250]='TSIG', [251]='IXFR', [252]='AXFR', [253]='MAILB', [254]='MAILA', [255]='ANY', [256]='ZXFR' } --- Whitelist of TLDs. Only way to reliably determine the root of a domain --@class table --@name tld local tld = { 'aero', 'asia', 'biz', 'cat', 'com', 'coop', 'info', 'jobs', 'mobi', 'museum', 'name', 'net', 'org', 'pro', 'tel', 'travel', 'gov', 'edu', 'mil', 'int', 'ac','ad','ae','af','ag','ai','al','am','an','ao','aq','ar','as','at','au','aw', 'ax','az','ba','bb','bd','be','bf','bg','bh','bi','bj','bm','bn','bo','br','bs', 'bt','bv','bw','by','bz','ca','cc','cd','cf','cg','ch','ci','ck','cl','cm','cn', 'co','cr','cu','cv','cx','cy','cz','de','dj','dk','dm','do','dz','ec','ee','eg', 'eh','er','es','et','eu','fi','fj','fk','fm','fo','fr','ga','gb','gd','ge','gf', 'gg','gh','gi','gl','gm','gn','gp','gq','gr','gs','gt','gu','gw','gy','hk','hm', 'hn','hr','ht','hu','id','ie','il','im','in','io','iq','ir','is','it','je','jm', 'jo','jp','ke','kg','kh','ki','km','kn','kp','kr','kw','ky','kz','la','lb','lc', 'li','lk','lr','ls','lt','lu','lv','ly','ma','mc','md','me','mg','mh','mk','ml', 'mm','mn','mo','mp','mq','mr','ms','mt','mu','mv','mw','mx','my','mz','na','nc', 'ne','nf','ng','ni','nl','no','np','nr','nu','nz','om','pa','pe','pf','pg','ph', 'pk','pl','pm','pn','pr','ps','pt','pw','py','qa','re','ro','rs','ru','rw','sa', 'sb','sc','sd','se','sg','sh','si','sj','sk','sl','sm','sn','so','sr','st','su', 'sv','sy','sz','tc','td','tf','tg','th','tj','tk','tl','tm','tn','to','tp','tr', 'tt','tv','tw','tz','ua','ug','uk','um','us','uy','uz','va','vc','ve','vg','vi', 'vn','vu','wf','ws','ye','yt','yu','za','zm','zw' } --- Convert two bytes into a 16bit number. --@param data String of data. --@param idx Index in the string (first of two consecutive bytes). --@return 16 bit number represented by the two bytes. function bto16(data, idx) local b1 = string.byte(data, idx) local b2 = string.byte(data, idx+1) -- (b2 & 0xff) | ((b1 & 0xff) << 8) return bit.bor(bit.band(b2, 255), bit.lshift(bit.band(b1, 255), 8)) end --- Check if domain name element is a tld --@param elm Domain name element to check. --@return boolean function valid_tld(elm) for i,v in ipairs(tld) do if elm == v then return true end end return false end --- Parse an RFC 1035 domain name. --@param data String of data. --@param offset Offset in the string to read the domain name. function parse_domain(data, offset) local offset, domain = dns.decStr(data, offset) domain = domain or "" return offset, domain end --- Build RFC 1035 root domain name from the name of the DNS server -- (e.g ns1.website.com.ar -> \007website\003com\002ar\000). --@param host The host. function build_domain(host) local names, buf, x local abs_name, i, tmp buf = strbuf.new() abs_name = {} names = stdnse.strsplit('%.', host) if names == nil then names = {host} end -- try to determine root of domain name for i, x in ipairs(listop.reverse(names)) do table.insert(abs_name, x) if not valid_tld(x) then break end end i = 1 abs_name = listop.reverse(abs_name) -- prepend each element with its length while i <= #abs_name do buf = buf .. string.char(#abs_name[i]) .. abs_name[i] i = i + 1 end buf = buf .. '\000' return strbuf.dump(buf) end --- Retrieve type specific data (rdata) from dns packets function get_rdata(data, offset, ttype) local field, info, i info = strbuf.new() info = info .. '' if typetab[ttype] == nil then return offset, '' elseif typetab[ttype] == 'SOA' then -- name server offset, field = parse_domain(data, offset) info = info .. field; -- mail box offset, field = parse_domain(data, offset) info = info .. field; -- ignore other values offset = offset + 20 elseif typetab[ttype] == 'MX' then -- mail server offset = offset + 2 offset, field = parse_domain(data, offset) info = info .. field elseif typetab[ttype] == 'A' then -- ip address info = info .. string.byte(data, offset) .. '.' .. string.byte(data, offset+1) .. '.' .. string.byte(data, offset+2) .. '.' .. string.byte(data, offset+3) offset = offset + 4 elseif typetab[ttype] == 'PTR' or typetab[ttype] == 'NS' or typetab[ttype] == 'CNAME' then -- domain/domain server name offset, field = parse_domain(data, offset) info = info .. field; end return offset, strbuf.dump(info, ' ') end --- Get a single answer record from the current offset function get_answer_record(table, data, offset) local line, rdlen, ttype -- answer domain offset, line = parse_domain(data, offset) table.domain = line -- answer record type ttype = bto16(data, offset) if not(typetab[ttype] == nil) then table.ttype = typetab[ttype] end -- length of type specific data rdlen = bto16(data, offset+8) -- extra data, ignore ttl and class offset, line = get_rdata(data, offset+10, ttype) if(line == '') then offset = offset + rdlen return false, offset else table.rdata = line end return true, offset end -- parse and save uniq records in the results table function parse_uniq_records(results, record) if record.domain and not results['Node Names'][record.domain] then local str = string.gsub(record.domain, "^%s*(.-)%s*$", "%1") if not results['Node Names'][str] then results['Node Names'][str] = 1 end end if record.ttype and record.rdata then if not results[record.ttype] then results[record.ttype] = {} end local str = string.gsub(record.rdata, "^%s*(.-)%s*$", "%1") if not results[record.ttype][str] then results[record.ttype][str] = 1 end end end -- parse and save only valid records function parse_records(number, data, results, offset) while number > 0 do local answer, st = {} st, offset = get_answer_record(answer, data, offset) if st then parse_uniq_records(results, answer) end number = number - 1 end return offset end -- parse and save all records in order to dump them to output function parse_records_table(number, data, table, offset) while number > 0 do local answer, st = {} st, offset = get_answer_record(answer, data, offset) if st then if answer.domain then tab.add(table, 1, answer.domain) end if answer.ttype then tab.add(table, 2, answer.ttype) end if answer.rdata then tab.add(table, 3, answer.rdata) end tab.nextrow(table) end number = number - 1 end return offset end -- An iterator that breaks up a concatentation of responses. In DNS over TCP, -- each response is prefixed by a two-byte length (RFC 1035 section 4.2.2). -- Responses returned by this iterator include the two-byte length prefix. function responses_iter(data) local offset = 1 return function() local length, remaining, response remaining = #data - offset + 1 if remaining == 0 then return nil end assert(remaining >= 14 + 2) length = bto16(data, offset) assert(length <= remaining) -- Skip over the length field. offset = offset + 2 response = string.sub(data, offset, offset + length - 1) offset = offset + length return response end end -- add axfr results to Nmap scan queue function add_zone_info(response) local RR = {} for data in responses_iter(response) do local offset, line = 1 local questions = bto16(data, offset+4) local answers = bto16(data, offset+6) local auth_answers = bto16(data, offset+8) local add_answers = bto16(data, offset+10) -- move to beginning of first section offset = offset + 12 if questions > 1 then return false, 'More then 1 question record, something has gone wrong' end if answers == 0 then return false, 'transfer successful but no records' end -- skip over the question section, we don't need it if questions == 1 then offset, line = parse_domain(data, offset) offset = offset + 4 end -- parse all available resource records stdnse.print_debug(3, "Script %s: parsing ANCOUNT == %d, NSCOUNT == %d, ARCOUNT == %d", SCRIPT_NAME, answers, auth_answers, add_answers) RR['Node Names'] = {} offset = parse_records(answers, data, RR, offset) offset = parse_records(auth_answers, data, RR, offset) offset = parse_records(add_answers, data, RR, offset) end local outtab, nhosts = tab.new(), 0 local newhosts_count, status, ret = 0, false tab.addrow(outtab, "Domains", "Added Targets") for rdata in pairs(RR['Node Names']) do status, ret = target.add(rdata) if not status then stdnse.print_debug(3, "Error: failed to add all Node Names.") break end newhosts_count = newhosts_count + ret end if newhosts_count == 0 then return false, ret and ret or "Error: failed to add DNS records." end tab.addrow(outtab, "Node Names", newhosts_count) nhosts = newhosts_count tab.nextrow(outtab) tab.addrow(outtab, "DNS Records", "Added Targets") for rectype in pairs(RR) do newhosts_count = 0 -- filter Private IPs if rectype == 'A' then for rdata in pairs(RR[rectype]) do if dns_opts.addall or not ipOps.isPrivate(rdata) then status, ret = target.add(rdata) if not status then stdnse.print_debug(3, "Error: failed to add all 'A' records.") break end newhosts_count = newhosts_count + ret end end elseif rectype ~= 'Node Names' then for rdata in pairs(RR[rectype]) do status, ret = target.add(rdata) if not status then stdnse.print_debug(3, "Error: failed to add all '%s' records.", rectype) break end newhosts_count = newhosts_count + ret end end if newhosts_count ~= 0 then tab.addrow(outtab, rectype, newhosts_count) nhosts = nhosts + newhosts_count elseif nhosts == 0 then -- error: we can't add new targets return false, ret and ret or "Error: failed to add DNS records." end end -- error: no *valid records* or we can't add new targets if nhosts == 0 then return false, "Error: failed to add valid DNS records." end return true, tab.dump(outtab) .. "\n" .. string.format("Total new targets added to Nmap scan queue: %d.", nhosts) end function dump_zone_info(table, response) for data in responses_iter(response) do local offset, line = 1 -- number of available records local questions = bto16(data, offset+4) local answers = bto16(data, offset+6) local auth_answers = bto16(data, offset+8) local add_answers = bto16(data, offset+10) -- move to beginning of first section offset = offset + 12 if questions > 1 then return false, 'More then 1 question record, something has gone wrong' end if answers == 0 then return false, 'transfer successful but no records' end -- skip over the question section, we don't need it if questions == 1 then offset, line = parse_domain(data, offset) offset = offset + 4 end -- parse all available resource records stdnse.print_debug(3, "Script %s: parsing ANCOUNT == %d, NSCOUNT == %d, ARCOUNT == %d", SCRIPT_NAME, answers, auth_answers, add_answers) offset = parse_records_table(answers, data, table, offset) offset = parse_records_table(auth_answers, data, table, offset) offset = parse_records_table(add_answers, data, table, offset) end return true end action = function(host, port) if not dns_opts.domain then return stdnse.format_output(false, string.format("'%s' script needs a dnszonetransfer.domain argument.", SCRIPT_TYPE)) end if not dns_opts.port then dns_opts.port = 53 end local soc = nmap.new_socket() local catch = function() soc:close() end local try = nmap.new_try(catch) soc:set_timeout(4000) try(soc:connect(dns_opts.server, dns_opts.port)) local req_id = '\222\173' local offset = 1 local name = build_domain(string.lower(dns_opts.domain)) local pkt_len = #name + 16 -- build axfr request local buf = strbuf.new() buf = buf .. '\000' .. string.char(pkt_len) .. req_id buf = buf .. '\000\000\000\001\000\000\000\000\000\000' buf = buf .. name .. '\000\252\000\001' try(soc:send(strbuf.dump(buf))) -- read all data returned. Common to have -- multiple packets from a single request local response = strbuf.new() while true do local status, data = soc:receive_bytes(1) if not status then break end response = response .. data end soc:close() local response_str = strbuf.dump(response) local length = #response_str -- check server response code if length < 6 or not (bit.band(string.byte(response_str, 6), 15) == 0) then return nil end -- add axfr results to Nmap scanning queue if target.ALLOW_NEW_TARGETS then local status, ret = add_zone_info(response_str) if not status then return stdnse.format_output(false, ret) end return stdnse.format_output(true, ret) -- dump axfr results else local table = tab.new() local status, ret = dump_zone_info(table, response_str) if not status then return stdnse.format_output(false, ret) end return '\n' .. tab.dump(table) end end