Only a few years ago, software applications tended to be isolated. Users of these applications were required to present themselves in a known location (for example, a bank branch or office block) that was protected by physical barriers to access such as locks, surveillance cameras, and security guards. Attacks against such software systems were fewer than are experienced today, in part, because gaining access to such a location presented a barrier that many found insurmountable.
The increased connectivity and prevalence of networked applications has removed the insurmountable barrier presented by physical security, and it is not only the networked applications themselves at risk. Increasingly, software systems control access to valuable physical resources (for example, banking software can be used to credit or debit a customer account). Subverting or compromising the software system may be the simplest way to gain access to the physical resource; for example, it may be easier to break into the banking application and create fictitious transactions than it is to crack open the bank vault.
Today, a talented 15-year-old Italian schoolboy, who would be unable to get past a company security guard, might, for personal amusement, be able to convince a networked application that he is a 37-year-old trusted employee from Alabama. More serious, however, is the increase in software hacking for criminal reasonseither to steal intellectual property or, more commonly, to steal information that can be sold to other criminals, such as lists of credit card numbers.
In short, the world has become more hostile towards software. In light of recent changes to social and political attitudes to security, it should be no surprise that the public has an increased expectation that software will be secure. The kinds of security that we discuss in this book can provide some protection against the increased frequency and sophistication of attempts to subvert applications. However, security has also become a tool to promote the sale of software, and claims of "unbreakable" security are now commonplace. The effective use of software security has fallen behind the ideal that is portrayed by marketing departments. Another purpose of this book is to close the gap between the perception and the reality, and to demonstrate how you can increase the security of your applications through the careful application of tried-and-tested technologies.