Microsoft pptp vpn vulnerabilities Exploits in Action

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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
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LAN, server may or may not have it’s own firewall software running locally.
This is an all to common setup. It is inexpensive and easy to setup and 
administrate. Many inexperienced administrators and users may use this setup, 
not being aware of how vulnerable a situation this is.
Advantages: Easy to setup and administrate, very low cost.
Disadvantages: Little to no protection, very vulnerable to many attacks, 
information “leakage” and more. 
Topology 2
VPN server behind a firewall but listening service ports still directly 
accessible for the ports that are allowed to be open by the firewall
This is another common setup. Inexpensive and still very easy to setup 
and administrate. This is an improvement over topology number 1. Unfortunately 
there are still many weaknesses easily exploited, and typically those who use 
this configuration rely too heavily upon the firewall to be their sole means of 
protection rather than “security in depth” and layering of defenses.
Advantages: Easy setup and administration, and low cost
Disadvantages: Still quite open and vulnerable to wide array of attacks.
Topology 3
VPN Server behind a firewall and only accessible to certain ports via port 
forwarding from the firewall.
This setup is an improvement over the previous two because of tighter 
restrictions on what traffic and services are allowed access and from where. 
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