1. Enforce HTTPS:

   • Always use HTTPS to encrypt data transmitted between the client and server. You can enforce HTTPS by configuring your application to redirect HTTP requests to HTTPS[1].
   • Example:

    app.UseHttpsRedirection();
   

2. Use Authentication and Authorization:

   • Implement robust authentication and authorization mechanisms to control access to your application. Use ASP.NET Core Identity or third-party identity providers like OAuth and OpenID Connect[2].
   • Example:

    services.AddAuthentication(CookieAuthenticationDefaults.AuthenticationScheme)
            .AddCookie();
   

3. Protect Against Cross-Site Scripting (XSS):

   • Sanitize user input and encode output to prevent XSS attacks. Use built-in HTML encoding features in Razor views[2].
   • Example:

    @Html.Encode(Model.UserInput)
   

4. Prevent SQL Injection:

   • Use parameterized queries or ORM frameworks like Entity Framework to prevent SQL injection attacks[2].
   • Example:

    var command = new SqlCommand("SELECT * FROM Users WHERE Username = @username", connection);
    command.Parameters.AddWithValue("@username", username);
   

5. Implement Cross-Site Request Forgery (CSRF) Protection:

   • Use anti-forgery tokens to protect against CSRF attacks. ASP.NET Core provides built-in support for generating and validating these tokens[2].
   • Example:

    <form asp-antiforgery="true">
        @Html.AntiForgeryToken()
    </form>
   

6. Secure Sensitive Data:

   • Store sensitive data securely using data protection APIs. Avoid storing sensitive information in plain text[2].
   • Example:

    var protector = _dataProtectionProvider.CreateProtector("MyApp.Purpose");
    var protectedData = protector.Protect("SensitiveData");
   

7. Use HTTP Strict Transport Security (HSTS):

   • Enable HSTS to ensure that browsers only communicate with your application over HTTPS[1].
   • Example:

    app.UseHsts();
   

8. Regularly Update Dependencies:

   • Keep your application and its dependencies up to date to protect against known vulnerabilities[1].

By following these practices, you can significantly enhance the security of your ASP.NET Core applications.

Is there a specific security concern or feature you'd like to dive deeper into?