November 2007
Intermediate to advanced
504 pages
13h 21m
English
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Chapter 12. Assessing IP VPN Services
This chapter tackles assessment of VPN services found running on network boundaries. Increasingly, VPN services provide access for both branch offices and home users, using IPsec, Microsoft PPTP, and SSL. These VPN service endpoints are under threat from information leak, buffer overflow, DoS, and offline password-grinding attacks, which are detailed in the following sections.
IPsec VPNs
VPN technologies and their underlying protocols fill entire books already. One book I used to research IPsec key exchange and authentication protocols is IPSec: Securing VPNs by Carlton R. Davis (McGraw-Hill). If you require detailed low-level information about IPsec and its various modes and protocols, you should read a book dedicated to the subject. Here I tackle the key IPsec protocols and mechanisms at a high level and discuss known remotely exploitable weaknesses and attacks.
Standard Internet Protocol (IP) packets are inherently insecure. IPsec was designed to provide security options and enhancements to IP, and to negate the following security weaknesses:
IP spoofing and packet-source forgery issues
Modification of data within IP packets
Replay attacks
Sniffing attacks
Most IPsec implementations use the Internet Key Exchange (IKE) service to provide authentication and key exchange when establishing and maintaining an IPsec connection. Some older IPsec implementations use manual keying, but this is now considered obsolete. After authenticating and negotiating ...
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O’Reilly covers everything we've got, with content to help us build a world-class technology community, upgrade the capabilities and competencies of our teams, and improve overall team performance as well as their engagement.Julian F.
I wanted to learn C and C++, but it didn't click for me until I picked up an O'Reilly book. When I went on the O’Reilly platform, I was astonished to find all the books there, plus live events and sandboxes so you could play around with the technology.Addison B.
I’ve been on the O’Reilly platform for more than eight years. I use a couple of learning platforms, but I'm on O'Reilly more than anybody else. When you're there, you start learning. I'm never disappointed.Amir M.
I'm always learning. So when I got on to O'Reilly, I was like a kid in a candy store. There are playlists. There are answers. There's on-demand training. It's worth its weight in gold, in terms of what it allows me to do.