Username enumeration
The first step to defeating a common user/password authentication mechanism is to discover valid usernames. One way of doing this is by enumeration; enumerating users in web applications is done by analyzing the responses when usernames are submitted in places such as login, registration, and password recovery pages.
In this recipe, we will use a list of common usernames to submit multiple requests to an application and figure out which of the submitted names belongs to an existing user by comparing the responses.
Getting ready
For this recipe, we will use the WebGoat application in the vulnerable virtual machine vm_1 and Burp Suite as proxy to our browser in Kali Linux.
How to do it...
Almost all applications offer the user the possibility of recovering or resetting their password when it is forgotten. It's not uncommon to find that these applications also tell when a non-existent username has been provided; this can be used to figure out a list of existing names:
- From Kali...
