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$23000 Authentication Bypass Lead to Arbitrary File Upload & Overwrite By Manipulating JWT

What is Authentication Bypass ?

So, an Authentication Bypass vulnerability is basically a big security problem because it lets bad actors bypass important login credentials or other security measures. This can happen when an attacker finds a way to sneak past the standard login requirements or other security protocols that are supposed to keep them out. Once they’ve found a way in, attackers can potentially access sensitive information or take control of a system, which can obviously lead to some serious consequences.

Essentially, attackers can find a way to gain access to sensitive data or functionality without having to go through the usual authentication procedures.


The Story

Algerian ethical hacker, Souhaib Naceri, known by the nickname h4x0r_dz, has recently uncovered a serious vulnerability in a bug bounty program.. The vulnerability involved bypassing the authentication mechanism by manipulating the JSON Web Token (JWT) and gaining access to the admin panel.

The target website used JWT for authentication, and through his expertise, Naceri was able to change the realm from “test-user” to “test-dashboard” by modifying the request in the login post request.

However, upon reporting the issue to the bug bounty program, Naceri was informed that the admin dashboard was just a client-side react application that was not critical enough to consider the issue as high severity.

Despite this setback, Naceri continued to investigate and attempted to manipulate the JWT scope, but to no avail. He also used content discovery tools like ffuf, but was unable to find any valid endpoints.

But, Naceri’s persistence paid off as he was finally able to find an upload endpoint that led to a file upload and arbitrary file overwrite vulnerability, which he managed to exploit.

With these findings, the bug bounty program raised the severity from Medium to Critical and rewarded Naceri with a sum of $23,000.

This discovery highlights the importance of persistence and determination in the field of ethical hacking and the potential rewards it can bring. The incident serves as a reminder to companies to keep their systems secure and to always be vigilant against potential vulnerabilities.


How to Prevent Authentication Bypass?

To prevent Authentication Bypass Vulnerabilities, here are some steps that can be taken:

  1. Implement Multi-Factor Authentication (MFA): By using MFA, users are required to provide additional authentication factors, such as a one-time code or biometric authentication, in addition to their username and password. This adds an extra layer of security to the authentication process and makes it more difficult for attackers to bypass.
  2. Use Strong Password Policies: Enforce strong password policies, such as requiring long and complex passwords, and implementing password expiration and lockout policies to prevent brute-force attacks.
  3. Perform Regular Security Audits: Conduct regular security audits to identify and address vulnerabilities in the authentication process.
  4. Implement Rate Limiting: Limit the number of login attempts to prevent brute-force attacks. Implement rate limiting on login attempts to prevent an attacker from guessing a user’s password by trying multiple times.
  5. Keep Software and Systems Up-to-Date: Keep the software and systems up-to-date with the latest security patches and updates to ensure that any known vulnerabilities are addressed.

By following these steps, developers and organizations can reduce the risk of Authentication Bypass Vulnerabilities and keep their systems and applications secure.



Link to full write up: here

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A cybersecurity practitioner with more than 5 years of experience in the cybersecurity world. Has an interest in creating simple blog websites, learning about SEO and graphic design, writing, AI, and understanding the concepts of journalism. Intentionally created this website to make the world of cybersecurity more engaging by combining it with journalistic principles and presenting cybersecurity stories that are easy to understand, which can help anyone who wants to develop in the cybersecurity world.



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