Common authentication flaws in web applications

We have spent some time discussing how different authentication mechanisms work in web applications. In this section, you will learn how to identify and exploit some of the most common security failures in them.

Lack of authentication or incorrect authorization verification

In the previous chapter, you saw how to use DIRB and other tools to find directories and files that may not be referenced by any page on the web server or that may contain privileged functionality, such as /admin and /user/profile. If you are able to browse directly to those directories and use the functionality within them without having to authenticate, or if being authenticated as a standard user, you can browse to the application's administrative area or modify other user's profiles just by browsing to them, then that application has a major security issue with regard to its authentication and/or authorization mechanisms.

Username enumeration

In black box and gray box penetration...