Microsoft pptp vpn vulnerabilities Exploits in Action

1.3 Various VPN technologies
There are many VPN options and technology components available, this 
document will primarily focus on MS PPTP (Microsoft’s implementation of Point 
to Point Tunneling Protocol).  Other technologies will be mentioned based on 
two major premises: popularity and availability. Many factors go into determining 
availability including: market proliferation, pricing, ease of use, security, stability, 
flexibility, performance, reputation, etc.
The VPN protocols mentioned include:
PPTP (Point to Point Tunneling Protocol)
MS PPTP (Microsoft's PPTP)
CHAP (Challenge Handshake Authentication Protocol)
MSCHAP (Microsoft’s CHAP)
MPPE (Microsoft Point to Point Encryption protocol)
IPSEC (Internet Protocol Security)
IKE (Internet Key Exchange)
L2TP (Layer 2 Tunneling Protocol)
CIPE (Crypto IP Encapsulation)
L2F (Layer 2 Forwarding protocol)
IPIP (Internet Protocol over Internet Protocol)
SSH (Secure Shell)