Book Image

Openswan: Building and Integrating Virtual Private Networks

By : Ken Bantoft, Paul Wouters
Book Image

Openswan: Building and Integrating Virtual Private Networks

By: Ken Bantoft, Paul Wouters

Overview of this book

<p>With the widespread use of wireless and the integration of VPN capabilities in most modern laptops, PDA's and mobile phones, there is a growing desire for encrypting more and more communications to prevent eavesdropping. Can you trust the coffee shop's wireless network? Is your neighbor watching your wireless? Or are your competitors perhaps engaged in industrial espionage? Do you need to send information back to your office while on the road or on board a ship? Or do you just want to securely access your MP3's at home? IPsec is the industry standard for encrypted communication, and Openswan is the de-facto implementation of IPsec for Linux.</p> <p>Whether you are just connecting your home DSL connection with your laptop when you're on the road to access your files at home, or you are building an industry size, military strength VPN infrastructure for a medium to very large organization, this book will assist you in setting up Openswan to suit those needs.</p> <p>The topics discussed range from designing, to building, to configuring Openswan as the VPN gateway to deploy IPsec using Openswan. It not only for Linux clients, but also the more commonly used Operating Systems such as Microsoft Windows and MacOSX. Furthermore it discusses common interoperability examples for third party vendors, such as Cisco, Checkpoint, Netscreen and other common IPsec vendors.</p> <p>The authors bring you first hand information, as they are the official developers of the Openswan code. They have included the latest developments and upcoming issues. With experience in answering questions on a daily basis on the mailing lists since the creation of Openswan, the authors are by far the most experienced in a wide range of successful and not so successful uses of Openswan by people worldwide.</p>
Table of Contents (22 chapters)
Building and Integrating Virtual Private Networks with Openswan
Credits
About the Authors
Acknowledgements
About the Reviewers
Preface

MD5 Insecurities


Every few months, a new article appears on the "holes" in the MD5 hashing algorithm. It is true that some uses for MD5 are now far less secure than originally thought. SHA-1 is affected in a similar way. However, these hashing algorithms are vulnerable for hashes stored long-term, for instance, MD5 hashes of binary files, such as those used to check file integrity by tripwire and the RPM package manager (for example when invoked with rpm -V openswan).

However, IPsec uses keyed MD5, also called HMAC. This means that an attacker would have to break an MD5 hash PER PACKET. And on top of that, all the mathematical shortcuts that these MD5 vulnerabilities are based on do not work for HMAC-MD5.

The greatest danger of MD5 and SHA-1 being broken is in their use within X.509 certificates, though even those are still considered to be safe for quite a while. The official IETF view is "walk, not run, to another secure hashing algorithm". Whether this will be SHA-256 or another algorithm is not yet known.