Secure Coding: Principles and Practices

5.4. Case Studies

In trying to select the most appropriate real-world examples to illustrate our recommendations in this chapter, we found no shortage of sad stories of organizations that made important mistakes in deploying their business applications. In fact, our main difficulty was in paring down the examples and deciding which ones would best illustrate our recommendations. It is all too easy to design an otherwise solid application and yet deploy it in an unsecure fashion, thereby wasting all of the time and effort that it took to put together a seemingly secure application.

5.4.1. Case 1: Faulty Telephone Switch

A few years ago, we were asked to review the security of a telephone switch for a client in the financial sector, as one component of a broader security assessment. Our review focused on the Unix-based computer that controlled the switch. The first step was to look at how the system functioned; here's what we found:

1. The small number of authorized users of the console system, as it was called, sat at their desktop PCs and used a simple telnet application to connect to the phone switch console and do their jobs.

2. Each user supplied the Unix system with a single shared username (with no password) to log into the system and run the application.

3. The application itself then prompted each user to provide a unique username and password, thereby performing all user authentication within the application.

Before ever touching any of the client's systems, we could already see ...