Broken Authentication

Broken Authentication  Medium

Authentication is probably the simplest and most widespread measure used to secure access to resources, and it's the first line of defense against unauthorized access. Broken authentication is currently rated #2 on the OWASP Top 10 Web Application Security Risks. A vulnerability or misconfiguration at the authentication stage can have a devastating impact on an application's overall security.

Created by Sandro "guly" Zaccarini

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This module covers common vulnerabilities and misconfigurations regarding Authentication that could be leveraged to gain unauthorized access to a web application. Specifically, in this module, we will cover:

  • An overview of authentication methods
  • Common protection mechanisms and possible bypasses
  • Attacks against login processes
  • Attacks against credential handling

This module is broken down into sections with accompanying hands-on exercises to practice each of the tactics and techniques we cover. The module ends with a practical hands-on skills assessment to gauge your understanding of the various topic areas.

As you work through the module, you will see example commands and command output for the various topics introduced. It is worth reproducing as many of these examples as possible to reinforce further the concepts presented in each section. You can do this in the Pwnbox provided in the interactive sections or your virtual machine.

You can start and stop the module at any time and pick up where you left off. There is no time limit or "grading," but you must complete all of the exercises and the skills assessment to receive the maximum number of cubes and have this module marked as complete in any paths you have chosen.

The module is classified as "Medium." Still, it assumes a working knowledge of how web applications and HTTP work, the Linux command line, basic Python and PHP scripting, and an understanding of information security fundamentals.

A firm grasp of the following modules can be considered prerequisites for successful completion of this module:

  • Linux Fundamentals
  • Web Requests
  • Introduction to Web Applications


  • What is Authentication
  • Overview of Authentication Methods
  • Overview of Attacks Against Authentication
  • Default Credentials
  • Weak Bruteforce Protections
  • Bruteforcing Usernames
  • Bruteforcing Passwords
  • Predictable Reset Token
  • Authentication Credentials Handling
  • Guessable Answers
  • Username Injection
  • Bruteforcing Cookies
  • Insecure Token Handling
  • Skill Assessment - Broken Authentication
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