o [NSE] Added the http-robtex-reverse-ip script that uses the Robtex service to

perform a reverse lookup in order to discover all names associated with the
  IP. [riemann]

scripts/http-robtex-reverse-ip.nse

@@ -0,0 +1,71 @@
+description = [[
+This script is inspired from http-reverse-ip to do a reverse ip lookup 
+using robtex website by parsing http://www.robtex.com/ip/ and return 
+maximum of 100 domains
+]]
+
+---
+-- @usage
+-- nmap --script http-robtex-reverse-ip --script-args http-robtex-reverse-ip.host='<ip>'
+--
+-- @output
+-- Pre-scan script results:
+-- | http-robtex-reverse-ip: 
+-- |   *.insecure.org
+-- |   *.nmap.com
+-- |   *.nmap.org
+-- |   *.seclists.org
+-- |   insecure.com
+-- |   insecure.org
+-- |   lists.insecure.org
+-- |   nmap.com
+-- |   nmap.net
+-- |   nmap.org
+-- |   seclists.org
+-- |   sectools.org
+-- |   web.insecure.org
+-- |   www.insecure.org
+-- |   www.nmap.com
+-- |   www.nmap.org
+-- |   www.seclists.org
+-- |_  images.insecure.org
+--
+-- @args http-robtex-reverse-ip.host IPv4 address of the host to lookup 
+--
+
+author = "riemann"
+license = "Same as Nmap--See http://nmap.org/book/man-legal.html"
+categories = {"discovery", "safe", "external"}
+
+require "http"
+require "ipOps"
+require "shortport"
+
+--- Scrape reverse ip informations from robtex website
+-- @param data string containing the retrieved web page
+-- @return table containing the resolved host names
+function parse_robtex_response(data)
+	local data = string.gsub(data,"\r?\n","")
+	local result = {}
+	for num,href,link in string.gmatch(data,"<span id=\"dns(%d+)\"><a href=\"(.-)\">(.-)</a></span>") do
+		table.insert(result,link)
+	end
+	return result
+end
+
+prerule = function() return stdnse.get_script_args("http-robtex-reverse-ip.host") ~= nil end
+
+action = function(host, port)
+	local target = stdnse.get_script_args("http-robtex-reverse-ip.host")
+	local ip = ipOps.ip_to_str(target)
+	if ( not(ip) or #ip ~= 4 ) then
+		return stdnse.format_output(false, "The argument \"http-robtex-reverse-ip.host\" did not contain a valid IPv4 address")
+	end
+ 
+	local link = "http://www.robtex.com/ip/"..target..".html"
+	local htmldata = http.get_url(link)
+	local domains = parse_robtex_response(htmldata.body)
+	if ( #domains > 0 ) then
+	    return stdnse.format_output(true, domains)
+	end	
+end