Security Risk: Console.log Exposes Login Error Details

Introduction

In the realm of web development, security should always be a top priority. One often-overlooked aspect of web application security is the handling of errors and how they are logged. In the context of a login component, exposing error details via console.log can introduce significant security vulnerabilities. This article delves into a specific instance where the Login component in a web application was found to be logging internal error details to the browser console, highlighting the risks involved and providing insights on how to mitigate such issues. By addressing these vulnerabilities, developers can enhance the overall security and reliability of their applications.

The Bug: Exposing Error Details via console.log

A critical bug was identified in the Login component (src/components/Auth/Login.tsx) of a web application. The component contained a console.log(error) statement within the OTP (One-Time Password) verification error handler, specifically on line 170. This seemingly innocuous line of code was exposing internal error details directly to the browser console. Such exposure poses a significant security risk because it logs authentication error structures publicly, violates established code quality guidelines, and offers no practical value, as errors are already displayed to users through toast notifications.

The primary concern here is the disclosure of sensitive information. When internal error objects are logged to the console, they can reveal details about the application's implementation, internal logic, and potentially sensitive data structures. This information can be invaluable to malicious actors attempting to understand and exploit vulnerabilities within the system. For instance, the logged error details might expose the structure of authentication requests, the nature of internal database interactions, or other critical components of the application's backend.

Furthermore, the presence of console.log statements in production code goes against established code quality guidelines. Logging detailed error information in the browser console is typically reserved for debugging purposes during development. In a production environment, such logs not only clutter the console but also increase the risk of exposing sensitive information to unintended parties. Best practices dictate that production code should be free of unnecessary logging statements that could inadvertently compromise security. Instead, errors should be handled gracefully and logged securely on the server-side, where they can be monitored and analyzed without exposing sensitive details to the client-side.

Steps to Reproduce

To better understand the vulnerability, here are the steps to reproduce the behavior:

1. Navigate to the /login page of the application.
2. Select the "Log in as Patient" tab.
3. Enter any phone number and request an OTP.
4. Enter an incorrect OTP (e.g., 000000).
5. Open the browser's DevTools (typically by pressing F12) and navigate to the Console tab.
6. Observe the internal error object logged, which contains authentication implementation details.

This simple reproduction procedure highlights how easily sensitive information can be accessed. Anyone with access to the browser's developer tools can view these error details, making it imperative to address such issues promptly.

Expected Behavior

The expected behavior of a secure and well-designed login component is that errors should be displayed to the user via appropriate channels, such as toast notifications, without exposing internal error structures in the browser console. In this specific case, the error should be communicated to the user through the toast notification that displays, "Invalid OTP, Please check the OTP and try again."

It is crucial that internal error structures are not logged to the browser console, especially in production code and within authentication flows. The goal is to provide users with sufficient feedback to understand the issue they encountered while ensuring that sensitive technical details remain confidential. This approach aligns with the principles of security by obscurity, which, while not a primary security measure, adds an additional layer of protection by reducing the information available to potential attackers.

Visual Evidence

To further illustrate the issue, a screenshot was provided showing the internal error object logged in the console. The image clearly displays the sensitive information being exposed, reinforcing the need for immediate remediation.

<img width=