http-vuln-cve2013-0156.nse

local http = require "http"
local shortport = require "shortport"
local stdnse = require "stdnse"
local string = require "string"
local vulns = require "vulns"

description = [[
Detects Ruby on Rails installations that are vulnerable to CVE-2013-0156, This critical vulnerability allows unauthenticated attackers to execute code remotely.
This is the nmap/lua port of the metasploit scanner module from hd moore

]]

---
-- @usage
-- nmap -sV --script http-vuln-cve2013-0156 <target>
-- nmap -p3000 --script http-vuln-cve2013-0156 --script-args http-vuln-cve2013-0156.uri=/xxxx,http-vuln-cve2013-0156.hostname=www.foo.bar  <target>
-- @output
-- PORT     STATE SERVICE VERSION
-- 3000/tcp open  http    WEBrick httpd 1.3.1 (Ruby 1.9.3 (2012-04-20))
-- | http-vuln-cve2013-0156: 
-- |   VULNERABLE:
-- |   Ruby on Rails XML Processor YAML Deserialization
-- |     State: LIKELY VULNERABLE
-- |     IDs:  CVE:2013-0156
-- |     Description:
-- |       There are multiple weaknesses in the parameter parsing code for Ruby on Rails 
-- |       which allows attackers to bypass authentication systems, inject arbitrary SQL, 
-- |       inject and execute arbitrary code, or perform a DoS attack on a Rails application.
-- |     Disclosure date: 2013-01-08
-- |     References:
-- |       http://cve.mitre.org/cgi-bin/cvename.cgi?name=2013-0156
-- |       https://groups.google.com/forum/#!topic/rubyonrails-security/61bkgvnSGTQ/discussion
-- |_      https://community.rapid7.com/community/metasploit/blog/2013/01/09/serialization-mischief-in-ruby-land-cve-2013-0156
--
-- @args http-vuln-cve2013-0156.uri URI Default: /
-- @args http-vuln-cve2013-0156.hostname sets the host header in case of virtual
--       hosting 
---

author = "h0ng10 (Hans-Martin Muench)"
license = "Same as Nmap--See http://nmap.org/book/man-legal.html"
categories = {"vuln","save"}

portrule = shortport.http

action = function(host, port)

  local uri = stdnse.get_script_args(SCRIPT_NAME..".uri") or "/"
  local hostname = stdnse.get_script_args(SCRIPT_NAME..".uri") or host

  local vuln = {
       title = 'Ruby on Rails XML Processor YAML Deserialization',
       state = vulns.STATE.NOT_VULN, -- default
       IDS = {CVE = '2013-0156'},
       description = [[
There are multiple weaknesses in the parameter parsing code for Ruby on Rails 
which allows attackers to bypass authentication systems, inject arbitrary SQL, 
inject and execute arbitrary code, or perform a DoS attack on a Rails application.]],
       references = {
          'https://groups.google.com/forum/#!topic/rubyonrails-security/61bkgvnSGTQ/discussion',
          'https://community.rapid7.com/community/metasploit/blog/2013/01/09/serialization-mischief-in-ruby-land-cve-2013-0156',
       },
       dates = {
           disclosure = {year = '2013', month = '01', day = '08'},
       },
     }
  local vuln_report = vulns.Report:new(SCRIPT_NAME, host, port)

  local resp1 = send_probe(host, port, hostname, uri, "string", "hallo")
  local resp2 = send_probe(host, port, hostname, uri, "yaml", "--- !ruby/object:Time {}\n")
  local resp3 = send_probe(host, port, hostname, uri, "yaml", "--- !ruby/object:\x00") 

  if not resp1 then
  stdnse.print_debug("%s:%s No reply to the initial XML request", host, port) 
	return
  end

  if not resp2 then
    stdnse.print_debug("%s:%s No reply to the initial YAML probe", host, port)
    return
  end

  if not resp3 then
    stdnse.print_debug("%s:%s No reply to the second YAML probe", host, port)
    return
  end

  if string.find(resp1, '[45]') then
 	stdnse.print_debug("%s:%s The server replied with %s for our initial XML request, double check PATH", host, port, resp1)
  end

  if string.find(tostring(resp1),'[23]') and resp3 ~= resp2 and resp3 ~= "200" then
	vuln.state = vulns.STATE.LIKELY_VULN
  end
  
  return vuln_report:make_output(vuln)
end

send_probe = function(host, port, hostname, uri, type, data)
    local data = '<?xml version="1.0" encoding="UTF-8"?>\n<probe type="' .. type .. '"><![CDATA[\n' .. data .. '\n]]></probe>'

    local options = {
        header = {
            Host = hostname,
            Connection = "close",
            ["User-Agent"]  = "Mozilla/5.0 (compatible; Nmap Scripting Engine; http://nmap.org/book/nse.html)",
            ["Content-Type"] = "application/xml",
        },
        content = data
    }

    response = http.generic_request(host, port, "POST", uri, options)

    return tostring(response.status)
end