How I Discovered a Weak Login Function Over HTTP That Exposed User Credentials

I hope you're all doing well and enjoying bug bounty journey.

In this article, I'd like to share one of my rewarded bug bounty findings involving an authentication security misconfiguration where user login credentials were transmitted over HTTP instead of HTTPS.

I'll walk through how I discovered the issue, verified the vulnerability, its potential security impact, and the remediation that can help prevent similar issues.

Let's get started!

##Introduction:

Authentication is one of the most critical components of every web application.

Even a simple configuration mistake can expose users' credentials to attackers.

During one of my bug bounty assessments, I discovered that a login page was transmitting user credentials over HTTP instead of HTTPS.

This meant usernames and passwords were sent in plaintext across the network.

The issue was responsibly disclosed, triaged, and rewarded.

##Understanding the Issue:

Normally, login requests should always be protected using HTTPS (TLS).

HTTPS encrypts communication between the user's browser and the server.

However, in this case, the login form submitted credentials through an insecure HTTP connection.

Example:

POST [http://example.com/login](http://example.com/login)

POST [http://example.com/login](http://example.com/login)

Instead of:

POST [https://example.com/login](https://example.com/login)

POST [https://example.com/login](https://example.com/login)

This exposed sensitive credentials to anyone capable of observing network traffic.

##Discovery Process:

While reviewing the authentication flow, I noticed that the login page was being served over HTTP.

To verify whether credentials were exposed during transmission, I captured the network traffic using Wireshark.

After logging into the application, I inspected the captured packets.

The username and password appeared in plaintext.

This confirmed that the application was transmitting sensitive authentication data without encryption.

##Why Is This Dangerous?

Whenever credentials travel over HTTP:

• Attackers connected to the same network can intercept requests.
• Usernames and passwords can be stolen.
• Accounts may be compromised.
• Organizations risk data breaches and loss of user trust.

Examples include:

• Public Wi-Fi
• Coffee shops
• Airports
• Hotels
• Corporate guest networks

##Key Takeaways:

Many organizations focus on vulnerabilities such as SQL Injection, Cross-Site Scripting (XSS), or Broken Access Control while overlooking transport security.

However, even a perfectly designed authentication system becomes ineffective if credentials are transmitted over an unencrypted connection.

Protecting user credentials begins with ensuring every authentication request is encrypted from end to end.

##Final Thoughts:

Bug bounty hunting is about paying attention to both complex vulnerabilities and basic security fundamentals.

Although this issue was caused by a configuration mistake, it had the potential to expose every user's credentials.

I hope this write-up helps other security researchers understand why verifying HTTPS enforcement should always be part of an authentication security assessment.

##Disclaimer:

This article is intended for educational purposes only.

The vulnerability was responsibly disclosed through the appropriate bug bounty program. Sensitive information has been removed or anonymized to respect the organization's responsible disclosure policy.