description = [[
Attempts to check if a login page exists on the port.
]]

---
-- @output
-- 80/tcp open  http
-- |_ http-login-form: HTTP login detected

-- HTTP authentication information gathering script
-- rev 1.0 (2010-02-06)

author = "Rich Lundeen <mopey@webstersprodigy.net>"

license = "Same as Nmap--See http://nmap.org/book/man-legal.html"

categories = {"ioactive"}

require("shortport")
require("http")
require("pcre")

portrule = shortport.port_or_service({80, 443, 8080}, {"http","https"})

parse_url = function(url)
  local re = pcre.new("^([^:]*):[/]*([^/]*)", 0, "C")
  local s, e, t = re:exec(url, 0, 0)
  local proto = string.sub(url, t[1], t[2])
  local host = string.sub(url, t[3], t[4])
  local path = string.sub(url, t[4] + 1)
  local port = string.find(host, ":")
  if port ~= nil then
    --TODO check bounds, sanity, cast port to an int
    local thost = string.sub(host, 0, port-1)
    port = string.sub(host, port+1)
    host = thost
  else
    if proto == "http" then
      port = 80
    elseif proto == "https" then
      port = 443
    end
  end
  return host, port, path
end

--attempting to be compatible with nessus function in http.inc
--in this case, host is a url - it should use get_http_page
--get_http_page = function(port, host, redirect)

--port and url are objects passed to the action function
--redirect an integer to prohibit loops
get_http_page_nmap = function(port, host, redirect, path)
  if path == nil then
    path = "/"
  end
  if redirect == nil then
    redirect = 2
  end
  local answer = http.get(host, port, path)
  if ((answer.header.location ~= nil) and (redirect > 0) and
      (answer.status >=300) and (answer.status < 400)) then
    nhost, nport, npath = parse_url(answer.header.location)
    if (((nhost ~= host.targetname) and (nhost ~= host.ip) and
        (nhost ~= host.name)) or nport ~= port.number ) then
      --cannot redirect more, different service
      return answer, path
    else
      return get_http_page_nmap(port, host, redirect-1, npath)
    end
  end
  return answer, path
end

action = function(host, port)
  local result, path = get_http_page_nmap(port, host, 3)
  --seems to be a bug in the matching
  local loginflags = pcre.flags().CASELESS + pcre.flags().MULTILINE
  local loginre = {
     pcre.new("<script>[^>]*login"    , loginflags, "C"),
     pcre.new("<[^>]*login"           , loginflags, "C"),
     pcre.new("<script>[^>]*password" , loginflags, "C"),
     pcre.new("<script>[^>]*user"     , loginflags, "C"),
     pcre.new("<input[^>)]*user"      , loginflags, "C"),
     pcre.new("<input[^>)]*pass"      , loginflags, "C"),
     pcre.new("<input[^>)]*pwd"       , loginflags, "C") }

  local loginform = false
  for i,v in ipairs(loginre) do
    local ismatch, j = v:match(result.body, 0)
    if ismatch then
      loginform = true
      break
      end
  end
  if loginform then
    return "Login Form Detected at " .. path
  end
end

So this takes every class C within the class B and checks to see if there are any IPs in it. If there are, it nmaps the ones that exist and writes them to their own file.

Also, the IP range is 10.1, so change as needed.

#!/bin/bash
for i in {1..254}; do
  cat iplist_sorted.txt |grep "10[.]1[.]$i" > /dev/null
  #if there are hosts on this class C
  if [ $? -eq 0 ]; then
    echo "nmaping $i"
    cat iplist_sorted.txt |grep "10[.]1[.]$i[.]" > ./ip_tmplist_$i
    #of course, specific scans will vary
    nmap -iL ./ip_tmplist_$i -sS -T4 -n -A -v --top-ports 2000 -oN ./nmap_10.1.$i.Xscan max-rtt-timeout 200
    rm ./ip_tmplist_$i
  fi
done