We have already seen the importance of information gathering in the previous chapter. Enumeration is the next logical step once we have some basic information about our target. For example, let's assume country A needs to launch an attack on country B. Now, country A does some reconnaissance and gets to know that country B has 25 missiles capable of hitting back. Now, country A needs to find out exactly what type, make, and model the missiles of country B are. This enumeration will help country A develop the attack plan more precisely.
Similarly, in our case, let's assume we have come to know that our target system is running some web application on port 80. Now we need to further enumerate what type of web server it is, what technology is used by the application, and any other relevant details. This will really help us in selecting accurate exploits...