Book Image

ASP.NET Core 5 Secure Coding Cookbook

By : Roman Canlas
Book Image

ASP.NET Core 5 Secure Coding Cookbook

By: Roman Canlas

Overview of this book

ASP.NET Core developers are often presented with security test results showing the vulnerabilities found in their web apps. While the report may provide some high-level fix suggestions, it does not specify the exact steps that you need to take to resolve or fix weaknesses discovered by these tests. In ASP.NET Secure Coding Cookbook, you’ll start by learning the fundamental concepts of secure coding and then gradually progress to identifying common web app vulnerabilities in code. As you progress, you’ll cover recipes for fixing security misconfigurations in ASP.NET Core web apps. The book further demonstrates how you can resolve different types of Cross-Site Scripting. A dedicated section also takes you through fixing miscellaneous vulnerabilities that are no longer in the OWASP Top 10 list. This book features a recipe-style format, with each recipe containing sample unsecure code that presents the problem and corresponding solutions to eliminate the security bug. You’ll be able to follow along with each step of the exercise and use the accompanying sample ASP.NET Core solution to practice writing secure code. By the end of this book, you’ll be able to identify unsecure code causing different security flaws in ASP.NET Core web apps and you’ll have gained hands-on experience in removing vulnerabilities and security defects from your code.
Table of Contents (15 chapters)

Fixing untrusted data deserialization

Missing type checks are not the only thing to look out for when it comes to deserialization—the data itself must be validated for its integrity.

Let's see in action how untrusted data deserialization can exploit our sample Online Banking web application.

Testing untrusted data deserialization

To test if our sample Online Banking web application is vulnerable to untrusted data deserialization, we follow these steps and use a tainted file:

  1. Navigate to Terminal | New Terminal in the menu or do this by simply pressing Ctrl + Shift + ' in VS Code.
  2. Type the following command in the terminal to build and run the sample app:
    dotnet run
  3. Open a browser and go to https://localhost:5001/Loans/Upload.
  4. Log in using the following credentials:

    a) Email: [email protected]

    b) Password: 6GKqqtQQTii92ke!

  5. Once authenticated, you will be redirected to the Upload Loan Application page. This page will allow a loan officer...