Studies in secure programming for admins



Like a poison apple, a Web program that is tasty on the surface may contain a highly dangerous core. Admins who do their own programming need to follow secure programming practices to avoid the bitter taste of insecurity.

This article describes some special kinds of program input that administrators who maintain Websites often contend with. I’ll present case studies that take a close look at problems and solutions related to cross-site scripting, malicious email addresses, and buffer overflows. If there is a theme to this discussion, it is that developers need to carefully validate all input and the relationships between various items of input. Assume all input is guilty until proven innocent. And the more complex this input is, the more important it is to code carefully to anticipate the actions of would-be intruders.