The Web Application Hacker’s Handbook Discovering and Exploiting Security Flaws

84

Chapter 4 

■

Mapping the Application

70779c04.qxd:WileyRed  9/14/07  3:12 PM  Page 84

---

Figure 4-8:  A generic error message created when an unrecognized file extension is

requested

Using the automated content discovery techniques already described, it is

possible to request a large number of common file extensions and quickly con-

firm whether any of the associated technologies are implemented on the

server.

The divergent behavior described arises because many web servers map

specific file extensions to particular server-side components. Each different

component may handle errors (including requests for nonexistent content) in

a different way. Figure 4-9 shows the various extensions that are mapped to

different handler DLLs in a default installation of IIS 5.0.