Microsoft pptp vpn vulnerabilities Exploits in Action

1.1 Conventions used in this document
Red colored networks, systems and devices, represent “hostile” or un-
trusted resources.
Blue colored networks, systems and devices, represent moderately 
trusted resources.
Green colored networks, systems and devices, represent mostly trusted 
resources.
Direct quotations of sources will be in 
italics surrounded by double 
quotes.
Commands from the computer terminal and source code will be 
formatted using the Courier Font.
Laboratory notes will be denoted using 
the Courier Font with Italics.
1.2 The basics of Virtual Private Networks
A Virtual Private Network, abbreviated as VPN, in it’s most basic terms, is 
the use of various technologies to provide a private network of resources and 
information over any public network, including the Internet.
VPNs provide a means for organizations and individuals to connect their 
various resources over the Internet (a very public network), but not make the 
resources available to the public, instead only making them available to those 
that are part of the VPN.
VPNs provide a means for such users to have resources scattered all 
over the world, and still be connected as though they were all in the same 
building on the same network together, with all the ease of use and benefits of 
being interconnected in such a manner.
Normally, without a VPN, if such a private connection was desired, the 
company would have to expend considerable resources in finances, time, 
training, personnel, hardware and software to setup dedicated communication 
lines.  These dedicated connections could be a variety of technologies such as 
56k leased lines, dedicated ISDN, dedicated private T1/T3/etc. connections, 
satellite, microwave and other wireless technologies. Setting up an 
organization’s private network over these dedicated connections tends to be very 
expensive.
With a VPN, the company can use their existing Internet connections and 
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