This book should be mandatory reading for anybody who is responsible for the security of a UNIX system.

Unfortunately, if you are a potential hacker, then this book can also provide you with lots of useful information, but it would be impossible to provide information to just one camp.

The point is made very early that the hacker's best tool is information; whether that is from somebody inside the organisation, from the computer itself or from the hacker network.

The book takes a logical approach as to how you can best secure your system from would be hackers.

It considers a single subject and explains how the hacker achieves their objective and what you, as a system administrator, can do to stop them. For example, one chapter describes how hackers could gain privileges to your system and what you can do to stop them doing this. This covers basic areas such as password control and also more specific areas such as the security risks posed if you are running an X Windows server.

Another chapter looks at the techniques that a hacker uses to cover his tracks, whilst leaving a trap door for later access. Again, specific measures are given as to how you can protect your system from this sort of attack.

A CD-ROM included with the book provides programs and information that are potentially useful to a system administrator.

In summary, if you are a UNIX system manager, responsible for security, this book should definitely be on your bookshelf, as well as your manager's to help convince him/her that the measures you take are justified.