Microsoft pptp vpn vulnerabilities Exploits in Action

How to protect against it:
Control what GRE packets are allowed through at the firewall. 
Unfortunately, GRE packets are easily spoofed. Another option is to upgrade to 
Windows 2000. Windows NT Service Pack 6a will not prevent this attack. It is 
possible there is a registry hack, or some hot-fix that was missed that may be 
available to fix this exploit, however I was not able to find such a fix that actually 
worked. Several were related, but after applying them, the systems were still 
vulnerable to this attack.
0

---