Introduction

Overview of the Challenge

In modern web applications, securely storing authentication tokens and associated information is essential to protect the integrity and confidentiality of user data. The issue becomes even more complex when considering the need to persist this information across browsing sessions without compromising security.

The challenge is how to balance the need for accessibility and security in these cases.

Article Objective

The purpose of this article is to explore a specific approach to this challenge using in-memory storage with Blazor WebAssembly on the .NET platform.

The intention is not to promote one technology over another, but rather to present a technical solution that can be adapted and evaluated by experts across various platforms and technologies.

Our discussion will focus on how in-memory storage can be used to store authentication tokens securely, while considering the implications of this approach, including its benefits and limitations.

Section 1: Contextualizing the Problem

The Token Storage Problem

Storing tokens and user information in a web application goes beyond just saving these data. The central concern is how to store them in a way that is both accessible and secure. An inadequate approach can expose sensitive information to attacks, while an overly restrictive solution can compromise the user experience.

Technologies like browser local and session storage, for example, are convenient but can be vulnerable to attacks such as Cross-Site Scripting (XSS). HttpOnly cookies are a secure alternative but have their own limitations, such as the difficulty of implementation in pure client-side applications like Blazor WebAssembly.

Thus, finding the right balance becomes a challenge.

Common Alternatives

  1. Local Storage: Commonly used but accessible by any JavaScript code on the same origin, making it susceptible to malicious scripts.

  2. Session Storage: Similar to local storage but restricted to the current browsing session. However, it shares some vulnerabilities with local storage.

  3. HttpOnly Cookies: Secure and inaccessible to JavaScript code but with limitations, such as difficulty in implementation in pure client-side applications like Blazor WebAssembly.

  4. In-Memory Storage: An approach that keeps the data in the application’s memory, more secure against attacks, but with the risk of losing the data during page refreshes or browser closures.

The complexity of these choices shows that there is no single approach that is ideal for all applications. Instead, the selection of a storage strategy should be carefully considered based on the specific security and functionality needs of the application.

Section 2: In-Memory Storage Solution with Blazor WebAssembly

Introduction to Blazor WebAssembly

Blazor WebAssembly is a client-side framework for building interactive web applications using C# instead of JavaScript. It allows the creation of rich components and the reuse of server-side logic and code. Running on WebAssembly provides benefits in terms of performance and integration with existing technologies.

In-Memory Storage: An Approach

When facing the challenge of storing authentication information, in-memory storage emerges as an intriguing alternative. In this section, we will describe this approach in detail, starting with its implementation.

1. Implementing the Singleton Service

  • UserService Class: A simple class responsible for storing the token and username.
public class UserService
{
    public string Token { get; private set; }
    public string Username { get; private set; }
    public void SetUser(string token, string username)
    {
        Token = token;
        Username = username;
    }
    public void ClearUser()
    {
        Token = null;
        Username = null;
    }
}
  • Registering the Singleton: Registering the service as a Singleton in Startup.cs or Program.cs.
services.AddSingleton<UserService>();

2. Handling Login

Using the service during login.

// Example code for the OnLogin function
if (response.IsSuccessStatusCode)
{
    var authorization = await response.Content.ReadFromJsonAsync<LoginFront>();
    _userService.SetUser(authorization?.Token, args.Username);
}

Technical Considerations and Limitations

  • Security: More secure against attacks like XSS compared to other approaches, but still sensitive to attacks compromising browser memory.
  • Persistence: Does not persist through page refreshes or browser closures.
  • Integration with Other Technologies: Easily integrable with other technologies within the .NET ecosystem, but requires special considerations if integrated with other platforms.

Partial Conclusion

In-memory storage with Blazor WebAssembly offers an interesting solution, but it is not without challenges and limitations. It is an approach that deserves consideration, especially when the specific security and functionality needs of the application are understood.

Section 3: Comparison and Possible Improvements

Comparison with Other Approaches

In this section, we can analyze the in-memory storage approach in contrast with the other techniques discussed earlier, such as local and session storage or HttpOnly cookies.

Possible Improvements and Extensions

While in-memory storage with Blazor WebAssembly presents an interesting solution, there are several areas where it can be improved or extended, such as:

  1. Enhanced Persistence: Experimenting with mechanisms that allow data persistence across page refreshes or restarts without compromising security.
  2. Integration with Multi-Factor Authentication (MFA): Extending the system to support MFA, further increasing security.
  3. Monitoring and Auditing: Implementing logs and monitoring to detect and react to suspicious behavior.

Section 4: Conclusion

The article explored the challenge of securely and efficiently storing tokens and user information. Through an approach focused on in-memory storage using Blazor WebAssembly, it was possible to identify a promising path that balances security and functionality.

Lessons Learned

  1. There is no one-size-fits-all solution: The choice of approach depends on the specific needs of the application.
  2. The importance of Experimentation: Exploring different techniques, even those less common, can lead to innovative solutions.
  3. The need for Continuous Evaluation and Improvement: The security and effectiveness of a solution must be continuously evaluated and adjusted as the application and environment evolve.

That’s all for now. If you have any questions or suggestions, please leave them in the comments. If you enjoyed this article, please share it with your colleagues.

Thank you for reading.