Security of Web Applications
Motivation
As we have seen in the previous chapter: Creating dynamic web pages from your server is easy. You can use CGI, PHP, Python, Perl, etc.. Also there are a lot of free and open source packages that you can deploy on your own server for a lot of different applications. Wordpress and other popular content management systems, etc..
The problem is to keep them secure. Here you learn the basic rules to follow and how to avoid the most common security issues.
Common Security Problems
Buffer Overflow
When you use compiled software (e.g. written in C) and the programmer is not careful, then it can happen that a buffer that is used to hold a string and is filled with data that comes from the outside user overflows and overwrites neighboring data. Often this is can be exploited to run arbitrary code on the machine.