Microsoft pptp vpn vulnerabilities Exploits in Action

How to use the exploit:
simply send malformed packets at the victim 
server (if providing PPTP services) on TCP/IP port 1723. There are any number 
of methods of doing so, the effective one tried here is using netcat.
Signature of the attack: 
Temporary increase of CPU utilization
•
0

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, Author retains full rights.
 
 
 
 
 
 
 
 
 
 
 
 
Key fingerprint = AF19 FA27 2F94 998D FDB5 DE3D F8B5 06E4 A169 4E46 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
Key fingerprint = AF19 FA27 2F94 998D FDB5 DE3D F8B5 06E4 A169 4E46 
 
© SANS Institute 2000 - 200
5                                                                                                                 
Author retains full rights.
26
PPTP Client’s unable to connect
•
PPTP Client’s unable to connect to any services inside VPN server’s side 
•
of network intermittently (during attacks)
System crashes to blue screen when trying to perform any application 
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function with message “KMODE_EXCEPTION_NOT_HANDLED”
System crashes to blue screen when trying to perform system shutdown, 
•
with message “KMODE_EXCEPTION_NOT_HANDLED”
Typical network packet signature of traffic during an attack:
As you can see, Ethereal cleanly discerns the “malformed 
packets”, it is simple to setup various IDS products to protect or respond to this 
network signature.